The speed of the games are fine and i dont think rebalancing is needed for any of the maps just fixing of small things. Not seeing any underpowered kits at the moment, as far as overpowered id say the SMG needs to fire more (use it like an smg) and lower LAT accuracy on light armored assets a smidge the rate light armor gets shot at is fine (HMV, Logi, Transport)
As far as shoveling emplacements id say the AT, AA, MG, FOB, and Razor wire be shoveled however they should be able to be done by one man (it would take longer with 1 man it simply should be possible) BUT if the AT, AA, MG must be shoveled they should be targeted less or at least less accurately by AT otherwise they would get destroyed too often making them not worth the time.
Foxholes and sandbags shouldnt be shoveled imo because the hard maps we need them on are ones with open flag caps with little cover that we dont have any time to shovel let alone place a single foxhole. (example Ia Drang, Charlies point, Fools road etc)
If you're making a racket on the flag with your tank and a bot spawns with an rpg he's going to target you through the wall because he can hear you and shoots instantly when you're in line of sight.
Humans can be more efficient with 2 hats than Bots can with 10 a good portion of maps we have many more heavy assets than them and when one of those assets has 300 kills thats not gameplay.