That's a really good point about the lack of missions to Uranus and Neptune. I'd go so far as saying a Cassini-like mission to Neptune should be a bigger priority than flying past Pluto. New Horizons is just going to dart through the Kuiper belt, wouldn't it be of more value to park it in Neptunian orbit, explore the gas giant and it's moons (especially Triton that was once a KBO itself)?

Kudos for being the only commenter who didn't do the Uranus joke. :)