And even if it is, orbital insertion requires a lot of energy, so a flyby is probably the only possible option.
I mean, really, assuming that all of the practical problems of building a probe and getting it to Uranus or Neptune were solved, wouldn't you just love to send it there and explore the $expletive out of them?
If you just want to eyeball the situation, take a look at Celestia.
I think orbital insertion is out of question for the outer planets using conventional space craft propulsion because the difference between high radial velocity required to reach the planet and the low tangential velocity of the planet itself is greater than the spacecraft's delta-v budget.
But there won't be another Voyager mission in our lifetimes, a suitable arrangement of planets happens only once in 400 years or so.