Personally, I think Wilder is playing a risky game. Lighting a fire under the owners is one thing but doing it by publicly flirting with walking out on the club is something else.
CW knows he has the backing of 99.9% of the fanbase but leveraging it to attempt to force the owners to give him what he wants, even though they're in the middle of negotiation / litigation (depending on which version you believe) and therefore unlikely / unable to conform, even if they would like to, could backfire.
Depending on his priorities (his career versus the club he supports) he might see himself in a no lose situation - no matter what happens he has enhanced his reputation and I'd likely to be offered bigger and better roles (whether Sunderland counts as either is another question).
My issue is that he has done it so publicly. He might see it as his only option but I feel he risks losing the backing of the owners by attempting to strong arm them and parts of the fanbase who once they get over their desperation that he mustn't be allowed to leave may start to look at it more rationally.
With things as they are (and not a million miles away from the circumstances under which he left Oxford) I suspect he'll go over the summer and I wish him well if he does but the club will remain and I will continue to support them even if the don't do as well next season and worst case, even get relegated.
Football is an odd business and one of very few that people expect or even demand you put your loyalty to a club above personal ambition. I don't blame CW for wanting clarity on what's going on at Utd or if he feels he'll be better off elsewhere but there are ways and means and CW actions over the last couple of weeks are not how I'd have played it.