Personally, yes, I agree that the Muppets have lost alot of what they used to have, but I've felt that way since LONG before Disney owned them. They are still some of the finest entertainment in existance today. Nothing, in my book, can compare with what the Muppets are.
Disney's aquisition was the last nail in the coffin for me. I know it's what Jim Henson wanted, but only as a large financial resource for himself and his creative team.
Now that Disney owns them the creativity has been, well, non existant. They were getting so close... then boom! Now the licence has about as much creative pizzaz as Ronald McDonald.