Avi K: The vast majority of Breslov chassidim were opposed to moving the kever to Israel. It’s far from clear Rebbe Nachman would have approved of such a move. He chose to move to Uman before his death for a specific reason — because it was near the graves of the Chmielnicki pogram victims, and he wanted to be buried near them.
Rebbe Nachman explicitly taught that the gravesites of tzaddikim literally have the kedushah of E”Y. So it’s clear he would be in favor of people visiting Uman from Israel–at least his chassidim.
However, unlike most other Chassidic rebbes Rebbe Nachman placed a great emphasis on the importance of visiting, and living in, Israel. (Rebbe Nachman taught that we should all yearn for visiting Israel even if we can’t, and Reb Nosson wrote many prayers on this theme–in Likutei Tefilos, which Rav Kook was known to often have with him.) For that reason, the vast majority of Breslovers live in Israel. Well-known Breslover rabbis, like Rabbi Lazer Brody and Rav Shalom Arush, are always trying to convince people to make aliyah.