I would love to see gameplay move back towards battlefield manipulation rather than just sniping skill. Guns that encourage destruction or construction are highly encouraged!
Dirt mortar would be pretty awesome. Perhaps some kind of mid-ranged block launcher for supporting team mates, you could safely construct barricades for the front lines, for example making some for your team to move up. Dirt grenades are another option, or perhaps a bouncing grenade that will leave a trail of dirt. You could go more extreme, for example a dirt bomb that explodes straight up making a pillar 10 blocks high or something, you could stand on it to quickly get height.
On the destruction end of things there are regular mortars, HMGs (with set up time), perhaps explosives like satchel charges for taking our larger areas, and RPGs or rocket launchers for taking out structures at a distance.
I am very vocal about not wanting to have many combat weapon choices, but as for battlefield manipulation I am happy to have a few more choices, for example 3 construction/3 destruction items. For example:
Main: semi, smg, shotgun
Destruction: grenades (as normal), RPG (2 or 3 shots, less damage than grenade similar splash), satchel charge (bigger aoe than grenades but very short range throw)
Construction: blocks, dirt grenades (grenades but make dirt :I), block gun (shoots blocks, not as much ammo as blocks, perhaps 30)