Wayne,
Not sure if bi-amping would help as much as you hope. The difference is in the panel improvements, IMO. The Xstat panel is something special. Speaking of Vantages, which is all I can speak of since I do not have Summits but the same principles apply, the active woofer is nice, however it is the new panel which makes the real difference. With my previous Aeon-i rock music was not as much fun to listen to as it was via headphones. Not by a mile, even in 2.1 mode. With Vantages, I can and enjoy it, too. What sounded good on Aeons now has more air (same observation as you made), speed, and resolution in time and sound stage depth and width.
I also believe that any amp suitable to improve your Odysseys via bi-amping is not likely to be cheap.
If you can wait until the CLX are released, but have a bad upgrade thirst to quench right now, consider adding an "i" to your Descent, and perhaps get a second one, too.