My first prediction is that what gets announced on a long lead time will be as nothing to what just 'comes out': a lot of indie ports together with puzzle games, JRPGs and visual novels. There looks to be a move from 3DS publishers to bring some of those games over as well.
I think Fallout 4 will come this year: Skyrim was received very well and it's probably made enough money to justify that. GTAV is more likely than Red Dead Redemption 2, but I wouldn't rule out The Warriors or Bully because Rockstar does like to support its old games.
Ubisoft will have a second Mario + Rabbids in development of course, probably for the end of the year, but I wonder about their larger franchises. Could we see a Watchdogs port? AC: Syndicate? Steep will be this year or never, but I'm not sure which.
I think we'll see a Nier:Automata port and something from Final Fantasy ... I hope it's XV but I could also see a case for XIV. Squenix has already got one of the lead JRPGs of the year in Octopath but I think we'll see more from them including the announcement of Bravely 3 for 2019. Most hoped-for would be Persona 5 but I've heard it said that there are exclusivity obstacles to that?
First party: I think Metroid Prime 4 is 2019 so a trilogy re-release would be great mid-year. So would Super Mario Galaxy in Autumn. I'm not convinced about Super Mario Maker: that one would be a surprise to me. Also, HD Skyward Sword would be a tough proposition unless they really overhaul that game, but they may be willing to do that. Yoshi & Kirby are not big enough to be the main titles for the year but would Animal Crossing or Pokemon be ready yet? I've got to doubt that. I could almost see a Switch Sports for holidays '18 as a more likely eventuality.
EA will have to reverse: VGChartz is today estimating Switch Fifa sales at a third of a million, which is peanuts (3%) of the total sales, but it was a bad port and it's too much money to leave on the table with the install base likely to double this year, so we'll get all their sports franchises now.
As for shooters ... Overwatch would be nice and I could see Fortnite coming this year. Whether we see a Call of Duty, Battlefield or Battlefront is very questionable but I think that someone is going to try to break that market this year.