My evidence is that HTTP/2 doesn't help much if at all for lightweight sites, especially if the site manages to hit my target of the first 10kB hitting the client rendering all the above-the-fold information, and especially if the clients are reasonably close to the server.

Indeed, given that HTTP/2 forces TLS (for any mainstream browser) which forces an extra RTT, for light pages my evidence is that HTTP/2 makes things marginally worse...

http://www.earth.org.uk/note-on-carbon-cost-of-CDN.html