The obvious shit first...sequels to long dead series that will probably never happen:
Suikoden, Lunar, Shining Force, Dragon Force, Final Fantasy Tactics, etc, etc.
Now for some more "pie in the sky" type of stuff that will definitely not happen:
1. A game set in the Warhammer Fantasy universe done by Rockstar. A fully realized Altdorf created by those guys where you play as a Witch Hunter. Will never, ever happen, but a man can dream, no?
2. Sticking with the Warhammer Fantasy setting, how about a For Honor sequel using that setting as it's base? For Honor has some sick looking character models and animations and a really unique combat system. But right now Ubisoft is just milking the shit out of the first game with no sequel in sight. Seeing a Chosen of Chaos fully realized utilizing the For Honor combat and animations would be freaking nuts. But they will probably just continue milking the first For Honor game until it quietly gets shut down. But don't worry, we will continue to get Far Cry games year in, year out.
3. A Souls game set in a D&D setting. These guys are the best at their creature designs so I want to see them tackle the Monster Manual and bring that shit to life.
Anyway, getting back from Fairly Tale Land how about something a bit more realistic? A 3rd person Resident Evil game that ISN'T a remake? Either a completely new game that progresses the story or maybe something that fills in a gap from the past games.