Clocked in at 97 hours after the credits rolled and I was returned to open world play. I did almost everything available in the game--there were two character quests left and a small dungeon to explore, one quest to take flowers to a grave, and two collection quests I left partially completed (I couldn't find anything useful online for the item locations and the game doesn't tell you either.) I don't have the DLC so I decided to just be done with the game for now, but I'll go back and knock that stuff out real quick when I either get access to a GS or buy the GOTY on the cheap.
The initial story is pretty dumb. The opening scenario is that the leader of the church (the Chantry), Devine Justinia, has called the warring mages and templars together to discuss peace. The peace meeting is disrupted by a giant rift opening and everybody present but the main character ending up dead. MC doesn't remember exactly what happened, but he's found unconcious and with some glowing thing on his hand that is connected to the rifts somehow. The people that found him accuse him of being behind the bomb or whatever, he agrees to go along and try to help close the rift, and you close the main rift. Doing so knocks you unconcious again. When you wake up everybody is fighting over whether you're a good guy or if you caused the whole thing in the first place, an Inquisition is called to work to find out what happened and to seal the remaining (smaller) rifts, and you're let loose upon the world.
I think they flubbed the opening story a bit. Rather than having everybody fighting over your legitimacy, nobody thinking much of you at all and just fighting each other instead would have worked better. Trying to make you out to be a big deal from day 1 just makes the story seem silly. By the halfway mark in the game you've got legitimacy from all the stuff you've done, but the opening is weak because of the approach they take. By about halfway through the story has picked up quite a bit and things are good, if not particularly unique or memorable. Overall the story and characters are certainly satisfying enough to justify playing it.
Since I didn't play the earlier games, DA:I used a default worldstate for which characters were around and how the earlier game story played out. If I'd played the earlier games then the dialogue and background events would have been changed accordingly. There are no huge differences that get brought in from early games, as best as I can tell, but reading about these differences when researching quests certainly made me more interested in playing the earlier games. DA:I also did a good job with the exposition so I didn't feel lost as to what had happened previously, so no need to feel like you'll miss out if you didn't play them either.
Gameplay-wise...you have two ways you can play; action mode and tactical mode. Action mode just has you running around 3rd person and targeting and attacking monsters and the like in real time. Tactical mode lets you pause the gameplay, switches to top-down view, and lets you plan each individual move out for your party members. I played entirely in action mode except for in big boss fights when I'd use tactical to tell everybody to drink a rejuvenation potion so they'd regenerate any damage taken during the battle.
The maps are good for the most part. There's some variety except for the couple of desert maps, which are just huge and boring. The main quests, character quests, and side quests all work out pretty well and don't get too repetitive. By the very end I was burning out a bit but it took quite a while to get to that point and I did a lot more than was necessary for the plat. If you're playing the game a bit slower or just doing the plat-required actions I don't think you'll have any problems.
The way the game opens up is that you complete quests and advance the main story line. As you do, you'll get power points. Each additional area requires a certain number of power points to open. If you open a new area that costs 30 power points and you have 35, you'll drop to 5 PP and then need to accumulate more to advance further. It works well in theory but the problem with this approach is that the game doesn't really guide you along a set path; advance to a certain part of the story and then you have a ton of game areas that you can open up but there's no real feeling of what order to play them in. I played the very first level, Hinterlands, almost to completion before going anywhere else. When I left I was level 15 and I found myself quite overleveled for half the available other areas to explore. Continuing to explore those areas just made me more and more over-leveled, which continued all the way to the end boss, who I crushed with no difficulty at all even in Nightmare mode. The lack of challenge was definitely a component to me feeling burnt out at the end--I was just getting bored at that point. If you play the game try to find a guide that suggests areas to play at for your level; while you can just completely explore each map in turn because the game is easy enough to tackle even over-leveled monsters, this process will definitely end up with your party extremely over-powered.
The character skills and classes have enough variety to provide for very different play styles. I used a rogue tempest bowman, which meant I basically nuked everything from afar. I had two tanks up in the action keeping taunt on the bad guys so they wouldn't chase me around and a mage as the 4th member of the group, throwing magical barriers around and doing resurrections and additional nuking. Based on your character class and focus you can change the AI around to cover your behavior in different manners. Going with the default AI controls isn't something I'd recommend as it doesn't optimize their behavior very well.
Gear is kind of a mixed bag in the game. There's some really cool stuff you can design but the UI for crafting is a pain in the ass. Basically to craft a weapon or armor you have to find or buy the appropriate schematic. The higher-end schematics are very pricy, some being in the 25k range. Just for comparison's sake there's a trophy for collecting 50k over the course of the game and I think I only gathered ~100k by the very end. The schematic pricing seems really high in comparison, and this is made rather frustrating because you can't tell anything about the the item stats before you buy it. If you want to know which armor is the best to craft for your mage you'll need to google it because the game won't tell you.
In addition, the inventory aspect of crafting is annoying because even if you know that a particular schematic calls for 40 pieces of metal, 16 pieces of leather, and 5 pieces of cloth to craft...you don't have an easy way to view your inventory to see your stock levels on those items. You'd normally expect that when you're in a shop and you're looking at buying a Dragon Scale, for example, that the UI would tell you how many of that item you already own so that you can buy the difference to get yourself to the 40 pieces of metal. Nope--instead you have to switch to the Sell menu, scroll down the list to check Dragon Scale stock, then back to buy to make your purchase. Then you have to repeat this again for every other item you're buying. There's no sorting capability, either, so you can't quickly filter by material type (metal, cloth, leather, essences, etc.,) or by the quality tier of the material. The process is just unnecessarily cumbersome.
Halfway through the game you'll get a new home base. For normal instant travel you go to the world map, select a local map, then select a camp or teleport stone on the map to jump your party to. This works quite well. The home base, Skyhold, doesn't let you choose a warp point, you always just appear in the center of the map and then have to teleport within the map from there. It has five warp stones, which is nice, but there are three map areas and all the warp stones are in the middle one. If you want to go to Undercroft (where all the shops are) or to your personal quarters you have to jump to the throne room, get through the teleport loading screen, and then go up or down the stairs from there, which triggers another loading scene. Poor design there and it gets a bit annoying with repetition.
Another annoyance is that every time you leave your home base (Haven at first, Skyfold at the halfway point) you have to choose which party members you want to explore with. I'd be fine with it if it gave you your previous party as a default and you could just confirm, but instead you have to manually select three of your ~10 characters every time you leave home. Since you go to the base over and over again to start operations, sell stuff, craft, or return quests this can get to be a bit annoying.
I did run into a few bugs, but for the most part they were very late in the game. One thing I noticed early on is that loot doesn't always drop where the corpse was. Instead it can drop at your own feet. I suspect this is a feature to help with distant enemies up on cliffs or other areas that are hard to reach, but since I played as a bowman and most of my deaths are at range I ran into it a lot.
The game does have framerate dips on occasion but nothing game-breaking. Texture pop-in is present but not bad. I did have the game perform very badly once upon suspension resume, at which point I just saved, closed, and re-opened the game to fix. Another point had the game speed completely thrown off so that I was moving in slow motion and could not pick up an item to clear a quest. Save/quit resolved that as well. No real problems otherwise.
The trophy list is pretty nice. There are missables but not many and as long as you're aware that they exist they're very easy to grab. The last missable is for making a particular choice near the end of the game--it changes the way the story flows from that point and most people online say the other choice is better. I'll go back and redo that decision when I go to play the DLC, but I was perfectly happy with the choice that gets you the trophy.