Id just like to point out that RTR was a lot more than just 6 maps (very good maps btw), it included 4(?) new tanks, AT guns, two new planes, 2 new armies which means news skins, weapon models and new voice commands etc for both sides. I dont see a fan effort being able to do this so fast and you dont have to buy it.
The map editor will be out Im sure, level editors have been available for most games for a long time and havent hurt their expansion pack sales.
Finally I respect Digital Extremes although I though UTII and UII were poor, but they are not the rule, they are more of an exception, not the rule.