That would be, for me, a massive step towards mainstreaming. I think the shunning & blood issue is one of the bread & butter differences between JW's and other evangelical christian groups. Once they lose those two things, i think it would further deligitimize them, not to the point of collapse (we can hope, but it wont happen), but i think this would cool the R&F, something they really can't afford.
I faded more than 6 years ago, I haven't even seen a JW in 4 years, I've pretty much moved on from the idea of rekindling 'friendships' with JWs.