I'd like the radius to decrease on most flags -
1) Once you finally capture the flag in question, it's easier to defend against the single player who attempts a reclaim.
2) Helps to justify leaving one man behind to defend, instead a whole squad, etc.
3) Reduces ambiguity as to which team has the true upper hand in the general location on the map
If you wanted to achieve that, then it would be better to
increase the flag cap radius so that the team with more numbers in the area gets the flag. I mean MUCH larger radius, so that players defending the town instead of the one building with the flagpole dont have to keep running all the way back to kill the dude under the table and recapture the flag (thus breaking the defense too).
Course it would make sense if the flag stays grey if there is more than 2 or so enemies, that way a squad could contest the flag and, if they can kill the defenders in the town, take it themselves.
NOT just sneak into the tiny flag zone and cap it while half of the other team are manning the defenses a little ways away...