1) I agree with eliminating as many roof penetrations as possible. Could be on the side (they do fridges in slides that way). The single biggest RV issue is leaky roofs, so eliminating that issue would go a long way towards better lasting RVs.
2) The vast majority of RV's are not sold to the full time market. Going camping for the weekend, most don't need a full length closet for suits and evening wear.
3) No thanks to on-demand hot water. Had one in our boat and it was a bear keeping a steady temp without leaving he water running.
4) You may see some tiny sinks but last 2 RV's we've had decent size double sinks.
PS: We've done a few Thanksgiving dinners. Most 2 burner stoves aren't large enough to a couple of big pots. The 3 burner stove is more about space to fit the pots.