I don't mind Baby Bear in short segments, if he improves his speech. I disliked some segments but I did like the street scenes where they found out Curly didn't like porridge, and the one where her growl is so huge. Though I think even that could come from a latent dislike of him, as that 2nd one was basically his being used as a straight man of sorts for the comical Curly growl. I just wish they'd used more older characters int hat one.
Elmo, however, is on way too much, and just isn't all that educational. His impediment is actually worse than CM's, but for another important reason. Cookie sounds gruffer, more like a monster, and I have heard 2YOs or 3YOs get their 1st person pronouns mixed up - "I want I ice cream" or "Me want that." That's normal for a child, so it makes sense that it'd be normal for a monster.
But, while several friends have assured me their kids don't try to copy Elmo's talk, it's totally abnormal for a child to keep inserting 3rd person into 1st person - the only poeple who do that are egotistical ballplayers and probably some Hollywood stars
And, you can picture CM shouting "Me want cookie!" just as he's about to graab and gobble up a cookie, the plate, maybe some silverware, too. It's actually less logical to picture him as a refined gentleman saying "I am going to eat this cookie and the plate and the table..."
But, it's totally un-monster-like for Elmo to say "Elmo wants to play ball. Does Telly want to play ball with Elmo?" His voice is not that of a monster, nor are his actions or attitudes, whereas Cookie Monster, 90% of the time when he's talking like that, it stands to reason that he's more than a little excited, and sometimes kids when they're excited sort of lapse back a bit in their language. ("Gimme" instead of give me, please" for instance.)