It certainly looks like Powell was holding all the aces when he was in negotiations for his job - if all the rumours of Trueman, Matuatia and now Holmes are true, then it's obvious he's been given strong control of recruitment & not being left open to any interference from Fitzpatrick.
It's a good thing that Powell gets to coach HIS squad and not have players lumped on him that he doesn't want (a problem Price has had). The only slight worry I would have, is that too much of a squad overhaul means we have a side needing a period in which players need to get used to each other and new surroundings and we end up with a situation like in the horrific Steve Anderson era, when players looked absolutely lost and performances and results suffer.
Obviously, the quality of players we will bring in will be higher than back then, but it can still lead to uncertainty among a squad - it will certainly be a good test of both Powell's coaching AND man management skills.