First and foremost...fucking TIMESPLITTERS 2 AND TIMESPLITTERS FUTURE PERFECT! For the love of god, please. Also I would LOVE a proper remaster of Resident Evil 3 Nemesis, my all time favorite Resident Evil game. It'd be awesome if they could remake it like they did with the Resident Evil Origins Collection. One other that would be really cool if they could remaster is Freedom Fighters. I played this so many times on the PS2, it's one of my all time favorite third person shooters. It really disappoints me that they never made a series out of it.
Also they've already made a PS4 remaster of the Jak and Daxter trilogy but it's a download only. I like have physical copies of my favorite games so I wish they would come out with a actual physical copy. Been holding out on buying the PS3 version because I thought they'd bring it over to the PS4.
There are many others but I'll just keep it at that.