I feel much the same, though I'm running bspwm, with my own cobbled together scripts rather XFCE. There's zero upside to me in an upgrade, but I worry it eventually will become hard to avoid.

I'm increasingly tempted to grab a simple Wayland compositor and "bolt on" a minimalist X implementation directly on it to also allow X connections with just enough of the protocol implemented to allow running some simpler X WMs (but I'd love it if someone beat me to it).

For WMs with lots of fancy stuff it'd can take quite a bit of the X API to support, but a simple X WM doesn't typically use that many request types (I just looked at i3's source, and it's X interactions are pretty simple...