1.) Gears of War 1 takes place 14 full years before E-Day. So there's no reason we can get a LONG Story in this game (or possibly an entire Prequel Trilogy leading up to Gears of War 1)

2.) Gears of War 2 had a great theme, All Out War. We had hundreds of Locust on Screen at once and it had such an amazing feel to it. Given that the COG are at full power just before E-Day, they should definitely be pushing for a total War style aesthetic in this game with the Locust Emergence.

3.) Campaign Replayability. Gears of War Judgement had a neat concept in it's campaign. "Declassified Information" which added random mechanics to each and every mission. Whether it's a Timer to finish the Mission, Weather Affects, Limited Visibility, Limited Weapon Options, Less Ammo Reserves, More Enemies ect. A system similar to this could definitely add some replayability to the campaign. However I feel like the Declassified Information was a good stepping stone it's not the best it could be as only a few of the mechanics that were altered really presented a challenge and changed your approach to the mission. A more enhanced version of this could definitely breath life into Campaign. Alternatively an additional system similar to Halos Skull System could be introduced (not instead of) but alongside Declassifieds system.

4.) 2 Player Split Screen Co-op and 4 Player online Co-op. With a reintroduction to characters we haven't seen in a long time. Tai Kaliso, General Loomis, Hoffman, Sam. D. Carmine ect. Maybe even getting to See Doms Maria for the first time briefly?

Lots of other things for Horde Mode.

Scoreboard. Customization Options. Lots of Weapons. Ect