Stewart did not win the Fiesta bowl. That was RR's team built from the ground up. All Stewart did was provide some levity to the team that already had all the pressure taken off by blowing the backyard brawl. All Stewart had to do was act as a cheerleader while the players let the muscle memory of all those repetitions and religious pounding of execution from RR take over. Or in other words, just relax and play free trusting all the practice from the year to flow without overthinking it. Also he let McGee actually call a few shots rather than running the safe zone reads over and over again.
Stewart inherited a great program and it significantly declined in his 3 years here. The roster of players wasn't bad, it was what he did with them that was lack luster. Holgorsen got his bowl win in similar fashion. Holgorsen inherited a talented roster with good football fundamentals already there. He then schemed a good way to use those player's talents. After that his weakness in recruiting players, instilling good football fundamentals, and maintaining discipline on the field was no longer compensated for and the program slid further. The two would actually have made a good HC combined as Stewart was good at getting players into the program and getting them investing in it while sucking at actually effectively using those players. Holgorsen was good at actually using talent, on the offensive side of the ball at least, but sucked at getting and developing that talent in the program.
In any event, Stewart's tenure outside of the Fiesta Bowl, which was much more on the previous coaching staff than him, was very underwhelming. 2008 lacked any real Marquee win and had 2 rather ugly losses against ECU and Colorado. 2009 was again without great wins, but understandable losses with the exception of the bowl game against a really subpar FSU team. 2010 was again no real Marquee win, but at least a valiant effort at LSU in a loss. However 2010 saw WVU almost lose to Marshall for the first time ever and then have utter garbage losses to Syracuse, UConn, and NC State that year. Note this was with a roster that included Stedman Bailey, Geno Smith, Tavon Austin, Noel Devine, Jock Sanders, Jeff Braun, Don Barclay, Najee Goode, Bruce Irvin, Scooter Berry, Chris Neild, JT Thomas, Keith Tandy. This was the year the WVU defense averaged only 12.75 points against during the regular season and never gave up more than 21 in any one of the 12 regular season games. So while Stewart's record looks decent, all of his wins were against teams that would be middle of the pack in the Big 12 and all of his losses save 1 were against teams of the same caliber or WORSE. So it wasn't that impressive and coming off the success and foundation of the 2005-2007 era it was downright bad.