It won't be too powerful, don't worry; seriously, 9th level maneuvers are equal to 6th level spells, and I'm pretty sure a Wizard limited to 6th level spells would be a Tier 3 character.
Actually... this is a pretty damn good base for PrCing, since you only go up in how many maneuvers you get to have prepared.
You could have it work as follows:
1. Have Readied and Granted maneuvers like a Crusader.
2. Have the list "scroll." The maneuver in the first slot only changes if you don't initiate any maneuvers that round.
How would this work? Say you can Ready 6 maneuvers, and that you have 3 Granted Maneuvers.
You start combat with 1/2/3 Granted. If you don't use any of them, you start next round able to use 2/3/4. If you use 1 and 3, for example, you get 2/4/5 the next round, and so on.
Now, if I've done my math correctly, you want to have at least double your Granted maneuvers in Readied maneuvers, because otherwise you could (if you got 5 Readied and 3 Granted) spam all 3 of your granted maneuvers, and then get one back the next round, which is kinda silly.
So I would say a
|Level||Maneuvers Readied (Granted)|
progression should work, maybe with a "you spin the Wheel of Maneuvers up to X spaces" class feature that you get later.
What you'll have to do is word it so you don't get idiot crusader abuse, but it'll probably end up fine.
And, the best part? If you use Maneuver Cards, you literally deal out your granted maneuvers, and leave your readied maneuvers in a stack next to it; any initiated maneuvers are placed on the bottom of the stack, you move cards to the left, and then you deal out cards until your Granted slots are full again.