One obvious change here is that it would make CA-signed certificates mandatory for all HTTP2 web servers - is that really a situation we want?
Who knows. Maybe that arrangement could even spur a sorely needed push for a free certificate trust network and get rid of CA's entirely.
StartSSL is one place where you can get a free cert for your website today (and yes, they charge for revocation, but revocation is pretty ineffective anyway). I got a free cert from them, but my mobile browser doesn't trust it, so I decided to shell out $10 for a cert that's more widely auto-trusted by browsers. Not a huge cost, IMO.
Regardless of the form of PKI employed, there's going to be a cost associated with validating the identity of the parties you're communicating with.
For the average Joe, certs that require domain ownership validation are pretty cheap these days -- certainly on par with domain name registration fees. As with domain names, people need to just start treating it as a necessary cost of running a website.
To be clear, I am far from a fan of X.509, but I'm not holding my breath for something better to come along (and be widely deployed) this decade. So let's use what we've got.