Fairly simple suggestion that will make the game experience 500% better. Take every employee that was involved with programming the player's AI team mates and promply fire every single one of them and then make sure they can NEVER work in the industry ever again. This will not only improve your next game but make every other game that gets released in the future better.
On a bit more serious note: After they announce the sequel or maybe even before that, they should have some kind of a official sticky where people can post their official requests for the next title. That would clear up the inevitable clutter that will be GR: Next suggestion threads after the first announcement teaser.
Unless they go for the biannual cycle I think the first announcement will be at E3 2019, but there will probably be a new splinter cell title before that. So the launch would be around Q2 2020.
Next instalment will be a sequel to Ghost Recon Future Soldier, appropriately named "Ghost Recon Space Marine" which will have all that futuristic **** that no-one asked for and requested features will be ignored. Also, only the main menu will be unlocked at the start of the game, everything else - campaign, multiplayer, all weapons, cosmetics, skills and everything else - will be locked behind paywalls.