Has anyone installed a desktop environment on open wrt on a raspberry pi? Seems like it would be heady. You could run console windows or open a browser and use luci directly from a keyboard and monitor.
There are tons of things you can do with OpenWrt, but desktop is not one of them.
OpenWrt is not suitable for use as a desktop OS. The main purpose of OpenWrt is routing and network and it is designed to be lightweight to run on the very modest hardware found in consumer grade routers (think 8-16 megabytes of storage and 64-128 megabytes of RAM. It doesn't even have a GUI system -- it is CLI only (it does have a web server and LuCI to enable the use of a web browser on a connected host as a GUI, but it doesn't have a web browser or any graphics capabilities within the core OS).
You could work the other way around -- using Docker or some other method of running VMs on your RPi, you could have the Raspian OS (or other 'desktop' release for the Pi) as your host OS, and then have guest OS's such as OpenWrt, if there are specific OpenWrt features that you want to run alongside your desktop OS.
What is it missing that it cant run a lightweight gui? It runs rather well on the pi3b+ which certainly has the hardware and memory. Im not suggesting running it as a desktop operating system, just providing a GUI and probably a basic web browser for system maintinance.
No X.org/ wayland, no qt (o.k., o.k., a very minimal and basic qt4/ qt5 is there)/ gtk3, no window manager, no browser, nothing at all.
Well, for starters, there is no graphics architecture at all as part of the OpenWrt environment. In other words, it has no concept of drawing anything to the screen except for text... It's kind of like an old dumb-terminal from the 1970's -- text only, no graphics. Maybe you could do something with ASCII art You could try to develop an entire graphics environment, but that would be a fairly significant effort. Because of the fact that graphics don't exist on OpenWrt, there are no packages with GUI's at all (except by leveraging the graphics/web browsers on another host). Oh, and there are no web browsers for OpenWrt, except for Lynx which is a text-only browser.