There is a tremendous difference in the build quality between your average TT slide and your average MH slide. Also, most motorhomes are designed to be quite usable with the slide in but that definitely cannot be said of TTs and 5ers.
I also think that floor plan becomes even more crucial in a MH with no slide if you will be staying in it for any decent length of time. I have seen some very nice layouts in the older ones with L shaped couches and such that would be very livable for 2 people. And yes, there are of course less potential problems when there is no slide.