I do love Marita (shame Mercury comes between it and Arras). C flag is one of the better ones for dropping a bomb on.
With regards to flanking options, there are vehicles which can be used to push through to enemy spawn flags when your team is under pressure. Also, the little path that runs around the side between B & D is surely a viable route on foot?
Light Vehicles which will get blown away the instant the enemy team sees it as half are running assault... all the paths between B and D are always locked down there is no viable flank routes they are all in the choke between b and D. There is less room to flank on this map than Metro lol and thats quite the feat.
Underground definitely ends in one team being trapped in spawn or home flag more frequently than Marita lol.
