sethnintendo on 04 October 2012
Command & Conquer went downhill after EA bought Westwood. I also stopped playing Sim City when EA bought Maxis.
I suppose you can add Paper Mario to the list even though I enjoyed Super Paper Mario (a lot of Paper Mario fans apparently didn't).
Sonic has fallen since the 16 bit era. I did enjoy Sonic Adventure 2 Battle a lot on GCN though.
