There are in fact some vague ideas floating around about using QUIC as a transport protocol for Tor. However, there is so much work to do and so few people that have the necessary skills (solid cryptography -- not at a "build the next AES" level, but "implement AES with no side channels" is already incredibly difficult -- plus low-level networking, C, and so on...) that in my view it is a minimum of 2-3 years from being mainstream available (look at how long HSv3 took).