Yes, I can see how Snape could be considered a "willing tool", but that's about the most I can see him being and that doesn't not eliminate the possibility of removal when the tool can do no more. -chuckle- I'll agree with Matt about the amusement factor, there. 'Twill be interesting to see the reaction if/when the full story comes out. Meanwhile, I do like the way things are building between Harry & Hermione in a subtle and slow manner; it'll last longer and build stronger that way.
I thought the initial part of the discussion with DUmbledore was amusing as Harry had to point out to him the clauses that'd allow removal of Umbridge et al. I can't wait to see the Ministry's reaction to being legally removed.