TL; DR at bottom*
Hopefully adding more verticality to future maps will make things much better to deal with.
Think about it, it will fix sniper problems because those issues mostly come from setting the reticle at head-level the whole time; it will cause more of a challenge for them.
Shotguns will have to be quick to get the jump on people.
Primaries will have more of a chance if they catch their enemies first.
Combined Arms was great. The huge maps were perfect because it was good for snipers, and there were ways to get around the map without being in the open.
This is just an idea, please tell me what you think.
TL; DR: Add more map verticality to counter these heavy reliances on "meta" weapons.