Instead of making continents the main factor in resources, I propse that on each continent the factions Warpgate determines the type of resources you acquire. Since the warpgates get rotated on a continual basis, each faction has an equal shot at getting resources on each continent.
Come next week all resources will be converted to a single category, "nanites" and they will be granted to everyone at the same rate on a per minute basis. It's up and running on the test server if you want to get a look at it. Further down the line there are plans to make the rate of nanite gain will be based on base power levels and will differ from hex to hex as a result, and there will be a whole sub game in keeping your bases powered and providing nanites.
So one faction has tanks, one faction has air, and the other has infantry? That may just be crazy enough to work!