Worst was with the discussion about Wayland having extra latency on mouse pointer movements.
The explanation there was that X11 used HW pointer device that got updated as soon as there was a change but that might lead to gasp occasional pointer tearing. So better add a couple ms of latency to everything in Wayland and sample the mouse pointer position once per frame.
FWIW, I do see screen tearing on my X11 multi-monitor setup. I just don't care.