Dynasty Warriors 7.
Dynasty Warriors 6 was a low point for the series, it wasn't that bad of a game (it grew on me after awhile) but it was still a pretty big decline from DW5. DW7 on the other hand fixed everything wrong with 6 and was exactly what was needed to make the franchise awesome again. DW7 also paved the way for DW8 (IMO the best entry in the franchise), which wasn't revolutionary or anything, it was more an improved 7 with a bunch of extra stuff. But considering they tried something revolutionary with DW6 and it just made the franchise much worse, sometimes a small incremental improvement to what you've already got is the way to do things.
Resident Evil 2 remake.
Seems kind of strange to include a remake here, especially since the main series of the franchise still hasn't returned to form for me (and probably never will) but I've got to give some credit to there finally being another good game that bears the Resident Evil name, even if it is just a remake.