When you log in, it choses the port # according to how many people are in the arena. If you disco'd and tried to log back into that same port number, you'd probably hang the entire system.
I just don't think they will ever change the network code that drastically just so you don't have to restart. Sorry but in my almost 8 years of experience here I just do see HTC doing that for what is a relatively minor annoyance.