Fightertown, Tank Town, and the like seem, IMHO, to be set up for quick action rather than the longer mission times in the rest of the MA.
If these mini arenas are to be sacrosanct within the MA, then it should be *impossible* to take them over. The mountains should be 30K+ surrounding them. On water maps, there should be a great empty sea surrounding these islands to discourage people from running a mission there. Disable troops at them. Disable ordanance if need be. Place cities and factories next to the towns and airfields for constant resupply convoys. Make it impossible to take down the FH's for any length of time or capture them.
As is with any online game, if something can be done, it eventually will be done, despite what individuals care to think about it. It happens.
How many defenders do you see up a fast fighter and ram the attacker that has flown for 15 to 20 minutes to get over a field to attack it in the first place? It happens.
How many spies are there with dual accounts that monitor the channels and set spotters near active fields to report what's happening to other countries? Or turncoats that give up their countrymen in channel 200 to the enemy? It happens.