I agree pretty much w/Philo & Gunge's order of things, but have a few things I think would be cool, as right now it's *too* organized, and as some have said, to juvenile:
Elmo's World: I don't mind it, but this kid reminds me of a naughty boy who's always in timeout in his room, as you *always* see Elmo's World in his little creation; after seeing it a few times I thought to myself, "Why is he always getting sent to his room/grounded!" Get Elmo's World out into his backyard, maybe to the playground as some have suggested bringing back, during that 10 or so minutes when you have it at the end. ANd, stop having him learn more on TV; it strikes me as an attempt to raise money for PBS or something, as you would think they would know that kids can learn by asking others, by reading a book, etc.
In fact, what happened to that deaf librarian? I was 6 in 1975 or so when she was introduced,a nd I remember that waas so cool at that time! Bring her into Elmo's World when he wants to find out more sometimes.
Mr. Noodle: I find this physical comedy hilarious! I'd have a big buildup where Mr. Noodle and his siblings are on the street various times, but don't say words yet, just do physical comedy. Have a big promotion to draw viewers, enticing them to come hear when Mr. Noodle says his first word. Then, at the end of the season, have the word be something really silly like "hippopotamus." (Might offend some Charlie Chaplain lovers, and I assume he'd sort of modelled after the silent movie star. But, you can always have that become a trivia question, the only time he talks.)
More classic sketches, including the restaurant coming back.
Varied people giving letter/number of the day, as was said.