> The first important idea is that in Wayland, every
> frame is regarded as "perfect." That is, the client
> application draws it in a completed form [...]
This is interesting, but also seems to run counter to recent work on the importance of very low latency feedback. See John Carmack's recent article on latency mitigation for VR headsets[1][2] for a very detailed example of this issue. Similar ideas also apply to touch[3][4] and even good old keyboard & mouse input schemes. There's a tradeoff between "perfect" frames and latency (see Carmack's post). From the quote, it appears that Wayland's design choice may limit achievable latencies for low-latency applications.
Low latency feedback is important for some things, but complete double buffering is the right default for a window system, because flicker is even worse than touch lag.
This is one of the reasons people think iOS is so "snappy." It goes to great lengths to never show you a partially-drawn frame. If you compare Safari to say Internet Explorer on Windows RT, you see that IE looks like ass when rendering complex pages, because it'll happily show you frames it's done laying out yet.
[1] http://www.altdevblogaday.com/2013/02/22/latency-mitigation-...
[2] #1 on HN: https://news.ycombinator.com/item?id=5265513
[3] https://dl.acm.org/citation.cfm?id=2380174
[4] https://www.youtube.com/watch?v=vOvQCPLkPt4