If there goal was just another edition, i would agree with you. But since their goal is to bring back lapsed D&D player (i think coming home is the language they have been using) it is on them to seek out and get feedback from the lapsed crowd. Personally I don't know if it is the case that they aren't doing that. It does appear they have reached out to the old school community for example. Where I think they may run into trouble is relying too much on their own forum for feedback (which is predominantly made up of 4e folks). Most news and playtest info (not to mention polls) hit there first and most frequently, so I suspect it is possible the playtest is weighted a bit in the 4e direction.
Wizards is ultimately responsible for the success or failure of 5E. If they fail to get the broadest mix of players in their feedback pool and therefore end up not achieving their goal of uniting the base they have no one to blame but themselves. It is not our responsibility as players to make sure the next editon gets the feedback it needs. If they really want feedback from people who didn't like 4e, we are easy enough to find.
But I will be the first to admit I am just not feeling "it" when it comes to participating in some of the feedback events they have set up. I hope 5e ends up good enough that I play and like it,it just isn't the focus of my life. I come here and therpgsite and happily share my toughts; I am not going to sign up for a account on the wizards forum because i dont currently buy their products.