At the risk of seeming foolish for asking a silly question, I'll risk it...
Why not have a rotating Restricted List?
Seems that there may be quite a few candidates drawn from the great custom maps that are out there, and there are maybe a couple of WoTC maps that could warrent a secont look. Why not select 6 or 7 maps from the pool of candidates for this year's organised play, then change to a different group of maps the next year, and continue to rotate it. Might be a way to freshen up organised play if every year there are all new maps to work with.. just a thought.
Feel free to rip it to shreds