Don't believe all the bad hype this game is getting. It's a great game. While the second game is pretty much just going back through every area you've been to and some other new ones, playing through the first game will be really enjoyable and if you like the game then the second and the online will be enjoyable.
The online is still very active. Most guilds are more active than others, but the top 100 guilds together probably have a thousand to a couple thoussand daily players.
If you don't get the gameplay so don't really enjoy it, then the online might not be for you. With the online though, once you increase your ranking above GR18 you'll be on far harder quests than anything on the story mode. The enjoyment you'll get out of playing through the quests and guild is getting more powerful equipment and using the best combination of attacks to attack every enemy with their weakness and trying to master playing as your chosen class or even cross class(which requires you to switch weapons in mid combat.)
Aside from Valkyria Chronicles, it's the best console JRPG I've played this gen and it's worth getting. I don't really count Yakuza, Demon's/Dark Souls, as RPGs, but it's better than Star Ocean the Last Hope, Final Fantasy 13, Resonance of Fate, and Blue Dragon to me(haven't played anything else.)