Should I play Inquisition? I loved DA:Origins
I'm very much a DA fan, so take this with as much salt as you'd like. There are events in DA2 that are relevant to the game. There are events in a DLC of DA2 (which I didn't play, and found quite confusing at first) that are very relevant to the game. But basically, the whole conflict between the mages and the templars has completely blown up. You have to make some sense into it, while fighting $VILLAIN. If you decide to give the game a go, just remember one thing: get the fuck out of Hinterlands. It's like your opening area after clearing the tutorial. There are several places in there where you are not supposed to go until much later. When you have enough "power", progress the main story. You can always come back.
(Also, if you're the kind that likes to clear every map marker out there, you will have a miserable time. Most of the side content is utterly forgettable and tedious. Unless you're a completionist, just gather enough power to progress the main story. There are some areas that you don't need to unlock, but which have awesome dragon fights or just interesting content - save that for the endgame.)
(Also, I don't usually recommend DLC, but Trespasser is pretty much a must. It tells the ending of the story, and sets up things for the next game. At least tries to, I don't know what's going on in BioWare.)