Re: Missing some basic animals.
None of the PHB1 classes have animal companions, so your biggest reason for needing a wide selection of basic animals is gone right there. Then you might fight a handful of animals at level 1, but after that you're on to bigger and more killtastic monsters, so I don't think that's a big loss.
Re: No centaurs.
I also am a bit sad that there are no centaurs. Mostly, though, it's just because I'm itching to do some Planescape in the new system and wish I had some inspiration for bariaur PC traits.