Yea Bevo gave them a great base to work with and great core of aussie players, who all work hard at both ends.
Gleeson helped them get 2 top imports (i know atleast Beal was his pick up, not sure if he was overly involved in the Ennis signing) and gave them a fair bit of freedom and confidence, which helped them take the next step. This type of things happens all the time, even when Smyth took over Adelaide he came in added Brooks and Mee and gave them freedom and we all know the results, guys like Cat had breakout seasons.
Some of the Perth players played a bit cleaner than last year, not sure if thats Gleesons coaching or the refs tightening up in general that caused that, but it resulted in the focus being on basketball, not purely beating the crap out of their opponent (albeit some games where cleaner than others).
To me thats what helped them take the next step, (Cedric Jackson leaving the NBL also helped!) and Gleeson deserves plenty of credit, but Bevo bringing guys like Martin, Knight, Wagstaff, etc to the club and working them very hard also helped.
I would say both Bevo and Gleeson (i was a fan of Gleeson at Townsville) are good coaches with their strengths and weaknesses and both have coached perth to a title each.
You could also argue that Clarke played his role at the 36ers bringing DJ, etc to the club, but no one is arguing Wright is a massive coaching upgrade.
So lets not downgrade Bevo or Gleeson both are good at what they do and most NBL clubs would be happy to bring Bevo in as coach if they had a vacancy id say.