To be honest, I love them in the anime. Their conflict and disagreement with the Inners is what makes them interesting to me. Before, it was like, here you just had the Inners with their idealistic philosophy, but here comes along Uranus and Neptune to shake that up and bring some depth and food for thought into the show. It's a classic moral and philosophical dilemma -- do the needs of the many outweigh the needs of the few? Would you sacrifice the life of an innocent to save the whole world? The funny thing is though, in real life, I actually probably agree more with Sailor Moon's more optimistic, idealized viewpoint, but on the show I find Uranus and Neptune more interesting to watch.
The one complaint I do have though -- as heartbreaking and beautiful as their betrayal episode is in Stars (it's ranked as one of my all time favorite episodes) -- is that I would concede that they do regress a bit in development. The Nehelenia arc shows them learning to work alongside the Inners, but then towards the end, they're back to doing their own thing again.
I also like how Uranus is more abrasive while Neptune is slightly softer and more compassionate. In general, I'm grateful to them for making Sailor Moon a more interesting and deeper show.

Can you imagine how boring the show would've been with just the Inner's idealized do-good philosophy in every situation?