Interesting to see this thread brought back to life, as this question was raised on a f'book coaches group just the other day. I believe my argument still stands in that the barriers to kids learning single handers are now removed by ROG, but I still don't see coaches teaching single handers (or even giving kids the chance to try one handers, which is probably more important).
I tweet - @ashtennis guru (no spaces)
I Shoot - www.flickr.com/photos/ashtennis guru/ (again no spaces! grrr)