Configuration of openHAB

That is not true. e.g. manual configuration of Z-Wave things does not allow setting of parameters.

That is what I am suggesting - that the gui is a frontend for readable configuration files.
Currently this is not possible.

Exactly!

I definitely see the need for auto-discovery and other nice features but why not have these just (pre-)create the configuration files. This way we could have the best of both worlds.