Ohhhhhh GOD! It's dripping! xP
As a fellow lover of Dynasty Warriors, I know exactly where you're coming from Jim. On the other hand, that's kinda a guilty pleasure seeing as how the DW games are almost all exactly the same, therefor failing your "need to be made" test. I like the improved graphics, the new characters, the various tweeks in interpretation to the stories and characters, but in the end if you've played one DW game you've pretty much played them all.
On the whole, though, I fully agree with your overall point. I used to be a big fan of the Assassin's Creed series. First game was fun, 2nd game was perfected, 3rd was pretty sweet and had a really fun multiplayer. And I believe after that is when they officially announced "Alright! Fire up the presses, time for a new game every year!" As such, Revelations was a rushed piece of crap, ACIII was just straight-up crap, and thus I have absolutely no intention of getting Black Flag. Like a piece of warm taffy, they've stretched and stretched and stretched that series until the story continue within it has become so thin and meaningless that it might as well not even be there.