I'm curious, what exactly is your reason for being so hell bent on taking them if you think they should be made uncapturable?
Having the center airfields makes it much easier to facilitate the land takes if that is what you are into. Basically gives you one more airfield at a central location to branch away from. They are large airfields, so very hard to pork for ords and troops, not to mention all the hangers. It's inherently obvious, the wider the front you have, more launch points, easier to flank, ect.
Problem is once you take the central airfields, you have to get the VH bases othewise they'll just run M3's and GV's to take it back. (then they call you a griefer in doing so)
I like Bronks idea of making the vbases uncapturable, combined with my idea of no spawn point back to the airfield...essentially isolating TT from rest of map.