Orb of Imposition- what part of "This saving throw limitation is part of a larger
effort to mitigate the use of saving throw penalties to
lock down enemies for the duration of an encounter." Is confusing you, given that was how you were building your character....
Why wouldn't you re-pick up an encounter power with the salve? I understand that change, the ability to re-grab a daily, especially for you, could swing a days worth of encounters, something they were trying to avoid with magic items.
Hide expertise doesn't surprise me- that was a ridiculous buff for one feat at mid to high levels and was talked to death on the boards.
As for implementing these changes- 9th level (for the buk of the party). Won't cripple your builds mid-level, especially given you are essentially mid-battle.