Fallout 5. At this point in time, whoever ends up headlining the development (Obsidian plz), it would be good to have it ready within the next 2 years or so, like in 2019. Its good to give a huge gap from the last numbered Fallout game in Fallout 4.
Borderlands 3. I don't exactly know how Gearbox can continue on from the story of the games, but considering that Tales from The Borderlands was allowed to have such a huge impact to the current lore of the game.
DOOM Reboot sequel. Yep. Nuff said. Of course. The game had a sequel bait with the campaign's ending and it would be nice to see more adventures of the Doom Marine as he ventures out into whatever unknown dimension he ended up landing at and just ripping and tearing through more demons and possibly even other outworldly beings such as other alien lifeforms and even human enemies.
Battlefield Bad Company 3.