Yeah, isn't Kev, like Executive Executive or something? he has a huge standing in Sesame Street outside of Lil' Elmo. Of course, he always had a lot of hats to wear... wasn't he the Puppetry coordinator for Dog City way back when? Heck, I'd be surprised if he was too busy to even be Elmo at one point, with all that he does.
However, it's being speculated that he recorded Clifford's voice for the LTS special, so we might just see him back yet.