No, not for every show, like Little Mermaid. I'll break it down...
--As much as we Muppet fans hate to admit it, Mickey is the reason most kids go to Disneyland or WDW.
--Mickey has a very popular show on Playhouse Disney right now that, in my opinion anyway, is a quality program.
--Bear has not been on for years (at least, in a regular slot) so most kids don't know who he is anymore (look at the Jerry Lewis telethon for proof)
--So, if I were designing this show, it would make sense to take Bear out and make Mickey the host of Playhouse Disney Live for that twofold reason: he's got a popular show, and he's Mickey.
Now, I am going to miss Bear's segments too, but it's time to move on, folks.