Garrison is a classic character and she always will be. Sure she got a sex change, but that doesn't make her much different than she was before. She's still the same freaky teacher who shouldn't even have that job that I grew to love.
It's kind of the principle of the thing. In the first few seasons, Garrison was a closed-minded, closeted homosexual male with a supposedly gay puppet. And now, (s)he's a closed-minded, straight female with no Mr. Hat to her name. It just doesn't seem right.