I just don't understand EA/Dice...
Keep in my mind I'm just spit-balling here, but it would seem the formula to make a successful modern military shooter is staring EA/Dice right in the face.
Grab the most beloved a.k.a. successful parts of their previous modern shooters (BF2 to BF4, with maybe a sprinkling of the stuff the modding community did with BF1942's Desert Combat) and roll them into one amazing new game.
Of course, KEEP all the so called "Legacy" features. You KNOW what the community wants in this regard.
Steer far and wide away from the "Hero Shooter" genre and focus on making Battlefield its own unique experience. Bring back classes, commanders etc. etc.
Maps.
Take the best maps or the basic formula of the most played/beloved maps and re-use them or at least make them a baseline for new maps. And I mean whatever worked, CQB or Vehicle-centric or middle of the road, whatever it was the community liked with these maps reuse them or build on that experience. What happened to the static anti-armor, anti-air and machine-gun emplacements? And please add MORE maps.
Vehicles.
Variety is the spice of life. This should be obvious, more vehicles, naval, anti-air, artillery, transports, air-assets, armor assets just MORE. Make them move and react with the environment realistically, have a higher skill ceiling. A good tanker or pilot etc. etc. SHOULD stand out. Bring back "sweet spots" for armor-to-armor battles.
Weapons.
Again variety, variety, variety. Make the weapons function differently, attachments that actually DO something beyond just the cosmetic. LMG's should have horrible spread, except when prone or bipod/braced on something. Sniper rifles SHOULD be inaccurate unless prone or bipod/braced on something, add scope-sway maybe even a little randomized wind-drift, offset that with removal of the scope glint (I mean c'mon the tech to decrease that in real life has been around for decades) Assault rifles SHOULD be OP, PDW's SHOULD be brutal in CQB etc. etc. You get the picture.
Soldiers.
I'll refer you to the K.I.S.S. principle, keep-it-simple-stupid. Make soldier movements somewhat grounded in reality, no endless sprinting, sliding, bunny-hopping etc. etc. Bring back the ability to peak/auto-lean around corners. And for crying out loud make the soldiers actually LOOK like soldiers.
Gadgets.
Again, I'll refer you to the K.I.S.S. principle, keep-it-simple-stupid. No flying squirrels, no spidermen, no magic shields, poke-balls, robot-guns or wall hacks.
Well that's all I can think of right now. but I think ya'll get the idea.
Maybe in the "next" Battlefield, eh?