I don't particularly think this would be a good idea, but it really depends on the situation. With one RT in Marine Start and one in each hive, that makes four total. You never want to have more then ten RTs in a map, and that only leaves six RTs, enough to make 3 Double node rooms.
It is well known that some nodes and node rooms are harder to hold, for either alien or marine (Reactor Room- Tanith), and while this is not usually a large problem, with only three rooms, things could get very ugly, very quickly. I do
know it would make comebacks very difffficult, because you could not ninja RTs up once you lost a few pitched battles for the RT rooms.
Thats only how I see it, because I can't imagine a Double Res room that isn't highly unbalanced.