First, as to Dragon's Dogma, it's not actually a sequel, it's more like glorified DLC that's being released as a standalone disc. Basically it's the same game, but with a whole new campaign that can be accessed after you finish the main game once, and they've also added a bunch of new abilities (from what I understand, all abilities used to have two tiers and will now have three tiers). And of course they've tweaked a lot of gameplay aspects, including adding in easier fast travel since people complained so much. In any case, it's probably only worthwhile if 1) You really, really liked the vanilla game, or 2) you never bought it in the first place, in which case the $40 price point makes it a more attractive prospect. But if you got the original game and were so-so about it, you may as well take a pass.
As to Kingdoms of Amalur, yeah, I bought it soon after it came out (the developer went out of business shortly thereafter). It was fine, I enjoyed the time I spent with it, but in the end it was nothing I'd write home about. Also, I was annoyed that in the console version you were so limited with the powers you could have active at any one time. They could have easily come up with a controller scheme where you could access more of them, which would have made it a lot more enjoyable for me. Oh, and it was too easy in general -- I played on the hardest setting from the get-go and rarely felt challenged, especially after my pure-mage class character started learning some of the higher-level spells. At the end it was just kinda ridiculous, really.
BTW, Dead Island: Riptide is getting slammed by critics for being basically the same game in a new setting. But this is one instance where I don't particularly care what the critics say. Even if it's just more of the same as the original, I can live with that. I still think I'll enjoy it.
