If shopping for an RV I would not even bother to look at a RV that had been "molested" with such modifications.
Replacing converters with newer multi-stage ones... OK, adding a EMS system when done neatly... OK, replacing a low end vent fan with a top of the line Fantastic Vent or Maxx Air... OK, Swapping faucets to better quality or single handle, again, OK when done properly.
Even conversion of a jackknife couch to a Futon style using the same mechanism but replacing the frames/springs/upholstery... OK (as long as old parts are saved).
Major re configuring of the interior.... Sorry, I would not look at it. Besides, I like a dinette
I'm just that way,
Charles