Star Ocean 3 & 4
- I love SO2. To me it just did everything right, from a fun battle system to lovable characters to a very effective character relationship system (that effected more than just which of X endings you would see). SO3 ditched, well, pretty much all of that. It was generic, the relationship system was totally different and the "twist" was not only dumb but it in a sense invalidated everything that happened in every other SO game. SO4 brought some fun back, but the battles were still less than they were in SO2. Characters were much better, and the relationship system was good on the surface, but once you looked a little harder it was obvious that it didn't really change anything meaningful (even the ending was set in stone).
Final Fantasy - Anything after 8
Up to FF8, I was a FF nut (with the glaring exception of FF5, which I find horrid). FF8 was a different beast than the others, but I didn't mind the system and the characters and story were very appealing to me.. then FF9 happened. Fugly character designs and a crap story that was just a forced reaction to the FF8 whiners. FF10 was good but not spectacular, and I never did get into playing as Tidus (really the only characters I liked were Rikku and Yuna to some degree). 11 should have never been a mainline FF game. I'm still bitter about that. 12 made the series into an MMO wannabe and totally lost the character focus that I had loved from the earlier games. And now 13 sounds like a totally linear progression of hall-> cutscene -> hall ..etc. *sigh*
Bonus marks for Zelda, Metroid and the Metroidvania games. Still very high quality gaming, but would it hurt to change them up at this point.. even a little bit? Keeping with what works is great, but when every single game in the series essentially plays the same, even if they change the visuals from 2D to 3D, you're not even trying anymore.