Story / World
Trails of Cold Steel II has a fairly decent story, but it still isn't without its major caveats here and there in how it does about certain things. You will find it makes use of some major tropes and cliches throughout the story. However in most cases it will be used in a fairly competent way that doesn't detract from the game or turns that trope/cliche on its head. You get more into the politics and general going on of the Erebonian empire. Since Trails in the Sky, they have become more competent at not being so painstakingly transparent with its hints at upcoming story plot. That does not mean, however, that there aren't some obvious things you'll be able to predict. Regardless, it does its job in a more competent manner in some ways than previous games in the series. Though I do think that there are a number of issues with regards to its main character that creates some bumps along the road in the story and I think most people would agree to at least an extent on this after having beaten the game.
The pacing was also improved over the previous Trails games we have localized as well. It still dips here and there in Cold Steel II, but overall I feel it was a big improvement. I also want to, but can't say anything on the ending itself because saying literally anything would be massive spoilers. Pretty much the only thing I can say though is that the game did quite well in eliciting an emotional response on several fronts, particularly in the latter parts of the game. This is mostly due to the emotional investment which Falcom has created by creating such an expansive and well thought out world and characters. When you finally get to save your Clear Data, I recommend everybody take some time to digest the story a bit before immediately swinging one way or the other.
The world on the other hand is expanded even further that goes as far as causing me to question my past train of thought. It will build new lore en mass throughout the entirety of the game as well as reference old lore without going into the level of detail the past games did as your characters experiences are very different than that of past game characters. You will see different sides of past lore to give you a bigger and sometimes different perspective on certain things. All-in-all it continues to grow and provide you with plenty of thought provoking scenarios for future games in the series.
Unfortunately the worst thing you'll experience playing Cold Steel I & II is that we don't have Trails of Zero or Trails of Azure localized. The stories take place parallel to each other to some degree. Without Zero and Azure, we are lacking a great deal of information and will come out of the game with a significant larger number of questions than we would have if we would have been able to play it before hand. That's not to say the story doesn't hold up without it as it does, but I feel like we're lacking so much context that it makes the lack of localization on Zero/Azure all that much more difficult.
Characters / Interaction
Next to how much lore there is in the game and series, characters and interactions is one of the best things about this game as well as series. Cold Steel II continues on the tradition of having great character building and presents it in a good way. This time around, unlike Trails in the Sky SC, the game I feel does suffer in the interaction between party members as a whole. Individually and in a smaller one on one setting I feel that they are still very strong, but when you bring everybody together I think it falls a bit flat and hits too hard on a few tropes/cliches that we commonly see in other games and shows. If I were to do some slight contrasting with another game, I'd probably pick Persona. In Persona, you have rather weak characters individually but as a whole they interact very competently when it comes to dialogue and interaction with each other as a group. If you're able to relate to that, then it's basically the exact opposite in Cold Steel II.
Now the one thing that people like to rave about, myself included, is the NPCs. Nearly all of them are named and if you continue to speak with them throughout the game after story progression points, you'll see that basically every named NPC has their own story arc going on. If you don't care about NPCs and talking to them frequently, then you're missing out on a lot of the game in my opinion. Due to how much dialogue NPCs receive, it gives you a greater perspective on what's going on in the world. Their own arcs may or may not intersect with your own, but it really does a lot to make the world feel more alive. On top of that it helps create an emotional attachment towards other characters, which will help elicit an emotional response during the story.
The one thing I do want to mention is that I feel Rean, the main character, isn't really a good main character. Even after spending time digesting the game after beating it, I still don't really know how I feel about him as character, let alone as a main character. There were just too many things that hinged on stupid explanations or decisions which I didn't particularly care for in how they handled him. That could also be part of the reason why we're getting Trails of Cold Steel III as well. There was one other character that I felt was handled pretty poorly, but I won't mention who.
Gameplay / Mechanics
Gameplay hasn't really changed since Cold Steel. It still has a very solid battle system that can be broken quite easily in the latter part of the game. What the battle system really excels at doing is turn manipulation as you can speed up, slow down, delay, interrupt and more to gain an advantage. On the other side of things, the difficulty is a bit lopsided where normal enemies are pathetic and bosses can be on the other end of the spectrum if you fight them normally. When I say normally, I mean without abusing certain setups that give you an insane advantage because if you use those, then even bosses are rather trivial once you are able to get the right equipment to make them possible. So if you're wanting some semblance of a challenge then I suggest avoiding using evasion tanks and gearing an attacker to becoming a literal atomic bomb. The same goes for abusing reflect and CP regen when possible. It's unfortunately very easy to become a god on the battlefield.
There are a number of new systems in place in the battle system too. You are able to go further with your links and unleash a new battle ability called Overdrive. Overdrive feels like a bit of a cop in and is insanely powerful when used correctly. Then besides that, the new "duel" battles since the previous game have been greatly improved. I use the word duel to describe them because they remind me a lot of the duels that you had in Suikoden. I really feel like they're an upgraded version of them and work very well with the context of the game. Those are the biggest addition to Cold Steel II, but I can't really go into details without spoiling some major plot points.
Other new mechanics are the new mini-games you'll encounter, including an updated version of an old one. You'll also run into Suikoden-esque recruitment that was really neat to see. You also have the special bonding event scene as well that I didn't really care much for in comparison to the first game. I'm not particularly fond of the direction they went with it, however I still have yet to see most of those scenes so my thoughts on it may change down the line. Besides those though, it's more or less the same as last time.
Graphics / Visual Presentation
This is easily the weakest point in the game as well as the series. The graphics aren't particularly impressive and the animations are nothing to write home about. However you will see updated animations of a number of things in Cold Steel II over its predecessor. I can't say whether this is to just improve animations or if it's meant to show character growth, but it has improved over the last game regardless. The biggest issue where this comes into play is the sections that cause the game to lag. I don't feel it's quite as bad as the final chapter was in Cold Steel I, but it's there and can be fairly annoying when it does happen.
The event scenes have improved slightly too, but are still greatly lacking. I feel like a bigger budget could really blow this series out of the water if they were able to work on the presentation of events, animations and the like. Despite this, for the most part the writing really helps make up for the lack of polished presentation.
Music / Audio
I'm not even remotely into music like the fanatical people of this thread are. Despite that, the music does well to both support the scene and help elicit an emotional response. You have a good number of tracks in Cold Steel II that stand out among others in the series. Not all seem to be included in the OST (Which the OST cover is spoilery if you haven't beaten Cold Steel I, so beware of Falcom Music Channel tracks for Cold Steel II/Sen no Kiseki II) unfortunately as there are a couple I would like to link but couldn't find.
These two are pretty good to use as an example I think.
The voice acting in this was really quite good. There were a number of characters that fit their respective roles very well. Some characters, such as Laura sound slightly different than the first game. I'm not sure if it's to show character growth, much like the new animations or what. I still felt Laura sounded ever so slightly off in how she delivered lines. Despite that, the new voices added were also very good. Considering I find that most English voiced dialogue in RPGs is rather lackluster and often bad, I feel they really knocked it out of the park with the large amount of voice actors used here. On the other hand, I still think that the voiced dialogue still suffers from a proper system to auto-advance dialogue to make conversations slow more smoothly. That is probably my only real complaint about the voice acting which is the fault of the game itself.
Conclusion / Final Thoughts
Despite the many flaws the game has, I think the game (Cold Steel I & II) are completely worth playing. Hell, I recommend playing through the entire series really. For me, the series as a whole really elicit feelings that I've only really shared with Suikoden and even surpasses that in my opinion. I'd probably even go as far to say that the Trails series is more than likely my favorite RPG series if I were to rank everything. It just does so much right from game to game that really helps me visualize and build the world as I see it. However despite that glowing praise, I do have to reiterate that Rean is easily the worst main character in the series based on all my knowledge. I really want to explain why, but it would hit on spoilers unfortunately and likely devolve into a rant. In the end it may be intentional as well and I have theories floating around in my head as to why. Hopefully Cold Steel III will fix him as a main character.
I really feel that more people need to play the Trails series in general, but I completely understand that the slow pacing can easily kill the experience for people.