I agree with a lot of what others have mentioned already.
I might be in the minority here, but I would fancy the next COD more in the World At War style.
I want a Pacific/Gulf Pearl Harbor style with mostly Japanese and American guns. A few German, Russian and British weapons sprinkled in.
No AK-47,74u or MP5'S. I want a simple 3 perk loadout and I want weapon attachments to feel specific and I DON'T want the guns to be generic with mono surpressors and agent field grips and no stock on everything. Launchers and specials get attachments.
It's ridiculous you can run 6 perks so you are immune to explosives/tactical equipment. You get scavenger and another perk whilst also being silent and being off the radar.
I think WaW is underated, the maps were awesome and some of the maps had tanks and they weren't a problem like more recent COD'S.
I don't want cheesy specialist operators and advantages that heavily change the flow of the game. Boots on the ground please.
I don't know why Treyarch haven't used WaW maps, only 2-3 in all this time. Whilst BO1 Firing Range, Summit,Jungle, Nuketown are constantly done.
Even BO 2 maps haven't been done much.
So yeah simplicity is the key for me as well and lot's of maps at launch and through the life cycle. 2-3 new maps every season.