Mistwell
Crusty Old Meatwad
I don't think they are doing so intentionally, as a function of their job or continuing market research, etc., though such a thing is not without precedence in business. "Shopping the competition" isn't a myth.
I also think that the videogame thread was more about the people on these boards looking for a better understanding than about sending a message to WotC. IMHO, that thread was less an EWT than a meta-EWT.
What I DO believe is that there are many game designers- freelancers and WotC employees, who frequent these boards and others. I doubt they actively participate in EWTs (at least, not very often), but they're definitely aware of them and may even lurk on one thread or another.
I'm also pretty sure that several of these designers play in multiple systems- not just 3.X and 4Ed, so they're conscious of gaming controversies and discussions in general. That the Edition Wars have moved on into more of a "cold war" phase isn't going to disappear from WotC's radar. If they enter the 5Ed design process down the road and the EWTs are still popping up and are still heated, and if there is any kind of 3.X market out there, they'll take a new look at it. I'm not saying that would make them make 5Ed resemble 3.X more, but it would probably make them reconsider some of the marketing bumbles they pulled in 4Ed's rollout. They'll probably also reconsider their market research and interpretation- IOW, they'll ask better questions, or they might cast a broader net.
Again, if that effect is real, it will have already happened. Continuing the edition wars doesn't make it happen "more". They are aware of the edition wars. They will not become less aware of them if they actually finally stopped. There is nothing about them continuing forever that helps the issue in any way. It's not persuasive at this point. It just further harms the community.