I was really hoping for Oprah, too. Oh, well.
We have to remember that what's most important to them (as far as the host goes) is who will get people to watch the Tony's that otherwise would not. Who has a large fan-base, aside from musical theatre? They know that the people that watch the Tony's faithfully and constantly attend Broadway shows will watch the ceremony (or attend the ceremony) regardless of who hosts.
Harvey Fierstein and Bruce Vilanch, despite how funny and talented (atleast the former) is/are, they will not bring in viewers. And as far as Charles Busch is concerned, funny man, great performer, but who outside of the theatre community even knows who he is?
Megan Mullaly is funny to an extent (when she's pretending to be Karen), but she doesn't have a large enough fan base - let's face it - the majority of WILL AND GRACE fans already have the Tony's on their to-do list on their Tivo's anyway.
Of course, it's possible that the producers might not be able to score ANY sort of celebrity that they want, which in that case, they might go for Hugh Jackmann, or someone like that.
Personally, although she has little to do with theatre, I think Ellen Degeneres would be a fantastic host. She would bring people in. If they kind find the person they're looking for, I also think Sarah Jessica Parker would be atleast an equal compromise.
"If you are going to do something, do it well. And leave something witchy."
-Charlie Manson