I know that some or many disagree, but I've always felt the shift from the Magoofs being "hands off" to "meddlesome" really started to show during the 2005-2006 season and after. That's when the Peja for Artest trade occurred then followed up by not retaining Coach Adelman that following Summer. Those of us that remember that time also remember the relationship between GP and Coach Adelman. There's little to no chance GP wanted to let Adelman go.
Also, I could be wrong, but I don't feel like Petrie would have traded Peja away for Artest if not for the Magoofs influence. I've also been staunch in the opinion that Petrie was more likely to draft Steph Curry at #4 in 2009 rather than Tyreke Evans -- who the Magoofs publicly defended at center court with the "it's changing" speech. I was actually quite surprised when Curry wasn't the pick.
Curry's skill set even back then was much more in line with the type of player Petrie coveted (shooting, passing, ball-handling, high BBIQ). Curry appeared to be at least Bibby 2.0. But Evans fit the mold of a larger version of Derrick Rose who'd recently won rookie of the year. I've always felt the Magoofs were overly intrugued with Evans and pressured GP into making that selection. GP is a class guy, so he's never much thrown the owners under the bus and taken responsibility for all basketball operations decisions, but there was a clear shift from Petrie's typical M.O. circa 2006.