One thing to make note of is that BFE often relies on horizontal cover such as low walls, cars, cement road diveders, etc... There are no rules for taking cover around corners and such yet, although an easy house rule I guess.
So even though you have a big city scape, if you don't place those low walls around to give cover, units will have to step out into the open to shoot.
Also, since this is a squad based game, those squads will have some trouble navigating around unless they break into fireteams. And even then they'll have trouble getting into a safe position to shoot at the enemy.