Frankly, you could play persona 4 without playing the others. You can pretty much just jump into any title. I'd also recommended them, they have great music, characters, gameplay, writing and it's just a really good experience.
Persona 3 Portable will forever be my favourite title.
Dragon Age 2 was okay. I think the reason why people were complaining was that it wasn't as open as the Dragon Age in terms of the start, and that the story faltered as a whole, but whatever.
Yeah, but it wasn't like the story for Origins wasn't just as flat and typical of Bioware, so if anything, at least Dragon Age 2 attempted something a bit more complex and offered different plotlines for each Act, rather than just "defeat the big dragon". That's not to say Origins didn't execute it wonderfully with the sidequests and worldbuilding, but the Origins story was pretty much just as weak as Dragon Age 2's, so that can't really be a huge point that they're trying to make. Plus, the story of Dragon Age 2 didn't have any major plot holes either, so it
was done rather decently.
Dragon Age 2's main downfalls were repeated environs and the story, and otherwise kept up the standard of Origins in terms of dialogue and writing, not to mention improving on the designs of the races and also fixing that annoyingly stale combat while keeping the element of tactics. There just wasn't any reason for the huge backlash for it, because there really wasn't anything major to complain about.
It just seemed to me like it was a huge case of bandwagon sequel hate. People expected the sequel to suck and by God they were going to react as if the sequel sucked, regardless of the fact that the sequel did in fact NOT suck.