Since other people are making suggestions for the game I figure I might as well give it a shot while I'm thinking about it, before I forget.
I really like super units so I was thinking that maybe for an extra dollar or two one could purchase the ability to have an extra one on their team instead of one or both of their scrolls.
Again with the super units, maybe have an alternate one for each team for download. Not for free though, of course.
Lastly, I think that traps would be a good addition to the game.
Feel free to state any feelings about my ideas. I'd like to know what my fellow players think and hopefully also the thoughts of someone from RE. :)