muttly13: Its not a Stracraft type RTS where you run to the best unit you have and pump out endless hoards of them
Rhineland: This is absolutely not how
Starcraft 2 is supposed to be played. Well, you can do it like that, but you won't get very far with that kind of "strategy". :)
Granted, its no strategy at all, but SC2 can and will continued to be won this way. I can build hydralisks and nothing but if I choose, and win. Complexity alone does not mean I have to abide by it in-game when simpler options will allow me to railroad the opponent. I am by no means saying its an end all, but its viable. Try building nothing but Knights in K&Ms and see how you do.
But before this gets into a SC love-in, I simply used it to juxtapose the depth of the economic side to address the original question. Its simply a much more in depth economic model than two resources and a unit cap. Different types of RTS, as much as RTS can be different to begin with anyway.