I thought the "Graduate" thing could've been done much better- why not have Jerry have an affair with the older woman? That would've been interesting- the speed dial thing just plain sucked. They should've had Elaine suddenly get engaged, and Newman crash the wedding screaming "Elaine, Elaine!" I could see that getting boffo laughs.
That's an excellent point. I think Jerry gets away with going out with women quite a bit younger than him (in real life and on the show) because he just seems so much younger than he is, in appearance and in his emotional and psychological maturity. He's a boy and will probably always be a boy. Will he ever get married? I doubt it.
The previous poster had some good ideas about what could have made the show funnier. Having a character named Elaine in both the movie and the show and not working that into the script was a wasted opportunity. My guess is that the writers didn't want to make the entire episode referent to The Graduate. Still having the good fortune of having a character on the show with the same name as someone in the movie and not taking advan....well, never mind.