think about it this way also...we (all us here) are looking at it from a Muppet fans point of veiw...question are those that say "jim parsons was the best part" die hard muppet fans or just casual Muppet fans when they see stuff at spencers or a Christmas special comes on, do they know others beyond kermit, chef, elmo, and beaker with out looking it up..that could be the factor too....but look at the good of what comes out of it...think when they are talking to thier friends and say "hey man did you see Sheldon in the new Muppet movie, no? you you have to check it out its awesome! he sings a song about being a Muppet thats hilarious" thats more word of mouth publicity the Muppets are getting.
now like what happened to Drtooth sucks..i know ive been there...a spoiler like that should never have been posted...its why i stayed away from the movie talk, sneak peaks and almost everything for a few months before it came out i didnt want to see the movie before i got in the theater