mdaniel parent
As a friendly reminder, SRV records exist and are great at fixing that magic port syndrome (unless you were hinting at the infinite corporate firewall appliances, for which I have no magic fix)
Right. Egress on anything other than tcp/443 is probably a non-starter for any new protocol.
The question I was alluding to is: if it's HTTP-ish over tcp/443, wouldn't it still be the web anyway?
But thinking about it more, the server could easily select a protocol based on the first chunk of the client request. And the example of RTP suggests that maybe even TCP would be optional.