I've done a couple of beers that were 100% oak smoked wheat malt (well, and a good helping of rice hulls). Neither of them got stuck, but the sparging was a little slow going. As for the beers, I enjoyed them both!
As I recall, a few months ago the guys at Basic Brewing compared a few 100% wheat beers with a batch made with 2-row. Tasting them blind, they were not able to correctly pick between the wheat and 2-row. hmmm....I would have thought that a 100% wheat beer would be dramatically different.