AFAIK Optimizations that reduce round trips, including that one, are very desirable for websites accessed over Tor. The communication with a website uses TCP, SSL, and HTTP as normal, TCP acks, etc are still needed and transported over SOCKS. So optimizations there will reduce time to first byte for the website accessed over Tor, and with Tor's increased latency, it's even more pronounced. Win.

But for TLS used in Tor itself, it's not as analogous. The analogous optimization would be looking at the cell  protocol and see if cells are small enough to fit in the initial congestion window.  I don't know, but what I would look for is something like Alice sending cells to Bob, but Bob can't reply to Alice's cells because Bob needs more data, but Alice needs to hear Bob's ACK before sending the rest of the data.