I've been playing Dynasty Warriors 5 (PS2). Mindless hack-n-slash with some very minor RPG-elements added to this particular entry. Just got it in a trade (very scratched, I'm sorry to say, but amazingly I have not run into 1 hiccup yet).
Even though it's so basic, I'm enjoying it. That could be because the last few games I played through were a bit more in-depth and maybe my brain is enjoying the mindless break.
But then I got to a mission I played through like 10 times, and I couldn't beat. So I gave-up and popped in Dynasty Warriors 2 (PS2) from my collection instead, that I hadn't played for years; basically it was like playing for the first time again. A little less graphical wow, and a bit of "fog" in the distance, and the text-boxes and style were different. But other than that, it was basically the same game minus the very minor RPG-elements.
3 entries later, and very little has changed in the series. It's amazing the series has lasted so long with so little change.