Gailey should never be lumped in with Switzer or Campo, and a few posts in this thread have bashed him without accurate evidence, in my opinion.
Gailey's offense was just fine and a great fit during the majority of his initial campaign in '98, with both the fans and with Aikman himself. Yes, he was unorthodox with a lot of his formations, but he was keeping teams that had pretty much memorized our Turner/Zampese formations and playcalls completely off balance. Don't forget that even with Troy missing 5 games in '98 he had Jason Garrett 2 points away from being 5-0 as his replacement in that offense during that stretch.
I don't think he tried to turn Aikman into Kordell Stewart at all, but the offense did give Aikman more liberty to take off, which he did with some pretty good success that season. Gailey also had a good eye for receivers I think, and he had both Ernie Mills and Patrick Jeffers performing at a high level that year.
Then in the offseason leading up to '99 (not the one leading up to the 2000 season as someone had said earlier in the thread) Jerry traded the 3rd to Holmgren for McKnight and we also nabbed Raghib Ismail in free agency. Suddenly we looked like a lights-out offense going into that summer, and then McKnight promptly tore up his knee in the first preseason scrimmage that July. Regardless, we were 3-0 and most likely heading to 4-0 that fateful day at the Vet when Irvin went down for what turned out to be his career.
Anyone remember the next several weeks after that? Down went Mills, down went Wane McGarity, down went Deion Sanders, down went even Jason Tucker for a while with some bad toes. Ismail was getting the snot beat out of him every week while trying to play the No. 1 receiver in one of the most underrated seasons by any Cowboys player in recent memory. Aikman was stuggling with a large degree of inexperience at receiver and started to lay the blame on Gailey's offensive system all of a sudden.
In the end, it's pretty much common knowledge that it was his constant talks with Jerry behind Gailey's back that got Gailey his hire-an-offensive-coordinator-or-get-fired ultimatum by Jerry that January. That was when Jerry was still letting players run the show and was short on patience. I also remember that Deion was having a mini-feud with Aikman in the locker room at that point, and took Gailey's side and basically said it was the "superstars on the team" that had to show up for big games and weren't (after the wildcard loss to the Vikings that was the final game of Gailey's coaching career). I've always thought there was a lot more going on behind the scenes during those two seasons that anyone has ever let on, and I wish JJT or someone who was around then would have written something up about that specific period.
I've maintained that if Jerry would have had sufficient patience with Gailey, he may very well still have been here today. One other ringing endorsement Gailey received for his time here was from Emmitt himself, who commented on Gailey's website that Gailey was responsible for resurrecting his career and helping him to the last 2 best rushing seasons he ever had.
Needless to say, I'm very happy for Chan's success this year.