That would work, if teams gave a rats about the flag in 7man...or XBall for that matter. The flag is an after-thought, and even if there was a single flag in the centre, it is doubtful that teams would even bother before every member of the opposing team has been eliminated.
I wouldn't say all of the guys who play XBall at its many levels (div 1-3 PSP, NXL, EXL, Open) were athletes with high levels of fitness..... It's not a necessity but just like 7man, as teams are picking up the fit 17 year old bunker monkeys, if you want to win then you've gotta match them.