Well, I can excuse Croaker, since KSY is a film and not a documentary. Croaker the "Actor" isn't the same Croaker that Kermit presumably grew up with.
What bothers me though, however irrationally, Robin's still an adorable little frog!
I was kind of hoping they'd take advantage of Vogel's casting and make a slightly older looking Robin. I understand completely the reasons why they didn't, but when you have Kermit interviews introducing him as being 55, it makes you realise that Robin must be 43 by now!