You kinda missed the point.
Windham left the WWF only a few months after debuting as the Widowmaker for family reasons. No he never got to the point of working with Hogan... because he wasn't there long enough to get to that point.
The Widowmaker was pushed pretty good upon his debut. Vignettes, hyped on Wrestling Challenge, the whole deal. He started doing the TV tapings in June and July... worked the house show circuit in August and September... and was gone by October.
He was given an undefeated streak during that time, and being that at that time, Barry Windham was considered one of the best wrestlers in the world, he was getting that push. Had he stuck around, he would have been working the main event within a year. Truth is... he probably would have been Ultimate Warriors 1st opponent after he won the title instead of Rude... or his second instead of Savage, and if that was the case, it might have even meant a title run. At the time, the first challenger to a new champion never had a real shot at winning the title. After that though, if the champ wasn't drawing like they hoped, you did have an opportunity to be the new champ instead. At the worst, he's working with Warrior instead of Warrior doing six mans with the LOD against Demolition in the Fall of 1990, because McMahon would have loved to have a real worker like Windham in there to put over his work-challenged champion.
Barber actually raises a very interesting point. While the gimmicks weren't the same (Widowmaker was a lone wolf cowboy gimmick), the names are very similar, and if Barry had stuck around and gotten that character over like he easily could have (again at this time Barry Windham was one of the best in the world - he could have gotten the gimmick over huge)... then maybe they don't debut the Undertaker when they do, just because the names are too similar. Maybe they don't even go with the Undertaker character at all? I don't know when it was first conceived, but I wouldn't be surprised if it wasn't until after Barry had left the WWF. Maybe Mark Calloway does end up getting the Berzerker gimmick and John Nord comes in with the more natural Bruiser Brody gimmick he'd always used?
It's interesting to think of the what-ifs.