Yeah, certain Muppet characters like Baby Bear and Telly to a lesser extent are being seen less and less these days. There was a big shakeup a couple of years ago with Sesame Workshop overhauling its staff - many of their new staff members having come from Viacom - and part of their agenda was to reduce the number of characters appearing on the show to what they called a "Core Six," as most other preschool shows tend to have a small number of main characters of just three or more. Said "Core Six" consists of Big Bird, Oscar, Elmo, Abby, Grover, and Cookie Monster: that doesn't guarantee that all of these characters will be seen on the show in every episode, but that they are the six characters who you are most likely to see in any given episode. Of course, that also doesn't mean that other characters have completely gotten the boot either: matter of fact, Count, Ernie and Bert, and Rosita still appear quite frequently as well, and other characters such as Baby Bear, Telly, Prairie Dawn, and Zoe are still around, they're just being seen less and less.
The human cast, meanwhile, has officially been pruned down to Alan, Chris, and the newest addition Nina. Sonia Manzano officially retired a few years ago, and all the others are no longer on the series proper, but are still involved with other Sesame projects outside of the show.
As for Baby Bear, I really like what David Rudman has been doing with the character since Season 30 onward: prior to that, I found Baby Bear to be a rather annoying character: always whining and complaining about Goldilocks, always having tantrums whenever Goldilocks would show up, it was almost like an obsession with him - not to mention, like Kevin Clash's early Elmo, early Baby Bear had that gritty voice that could be quite irritating. But since Season 30, Baby Bear has become quite an interesting and fun character: he and Telly make a good pair, both have their moments of childlike qualities that test their friendship, but Baby Bear usually also tends to be the voice of reason between the two. I also enjoy the occasional little one-liners that Baby Bear will zing, such as the time Telly accidentally hurt him and tries to distance themselves as much as he can to avoid doing it again, to which Baby Bear tells him he would like to go back to playing together in close proximity, "at least within the same zipcode."