With the exception of the random internet analogue Dirge of Cerberus actually fit pretty well into the universe. The characters were a little to whiny, but OMEGA Weapon made sense in the context of the overall story.
Maybe, but I still can't stand that awful Vincent Valentine fanfic. Especially the part where he gets the 'girl' at the end.
Also DoC is the epitome of Noruma's awful character designs.
And even if the over the shoulder/third person shooter gameplay were any good back when it came out, it probably hasn't aged all that well in the face of all those Resident Evil games. Hell, if I recall correctly, DoC's gameplay is about the same level of quality as Bullet Witch's gameplay. (Besides, did it REALLY need those sneaking missions?)
But my beef with Before Crisis is that its conceptually identical to Friends of Mana (which is currently equal in the hasn't left Japan and the world hasn't missed much traits). And Friends of Mana was also part of an even worse Squeenix compilation that killed off the Mana series wholesale (Circle of Mana was the equivalent of Squeenix digging up the Mana series' cold, dead, rotten remains to tie up onto a pike to parade around for a while).