What I believe the BW-ers are missing is the fact that starcraft vanilla actually was a quite terribly imbalanced game that needed many, many YEARS to become what it is right now. If we compare the development of SC vanilla to what has happened to SC2 in merely a year it is pretty mindblowing. Not only is is just not fair to compare a game that has evolved for years with a game that's one year old - moreover people miss that we are have still two add-ons to go until we are set with the final bunch of units. Currently we are playing nothing more than some sort of glorified beta.
If you continue this thought-process, it's a GREAT thing when BW-players are switching right now, because the amount of feedback those people - especially the coaches, not only the players themselves - can give to blizzard is huge. If Flash, Bisu and Jaedong give their input on how to improve and balance the game....then SC2 could become amazing with the 2nd add-on.
Maybe we could agree on this thing: currently, BW is > SC2 in terms of balance and competitiveness. But if the top-notch BW-players start playing SC2, their input especially when it comes to balancing HotS and LotV could turn out to be priceless.