[ben_w]

Rockets are far too explody to put nuclear waste in space.

Vitrifying the waste and putting it in a cave would be fine if people weren't terrified of the stuff, but they are so it isn't.

[pfdietz]

"Explody" can be dealt with by armoring the waste. If the rocket explodes, retrieve the waste and try again.

In the near term, the clear answer is dry casks. They are simple, cheap, and foreclose no other future option. In about 300 years the waste ceases to be self-protecting against amateur diversion, but that's plenty of time for (for example) launch vehicles to space to become very cheap and reliable.