Scamps are somewhat different than Casitas. I can only help with that thought in mind since we have a 17' Casita.
Before making any changes in that wall it would be prudent to see what it would take to replace it, if changing it's shape were not successful.
In our Casita, that wall conforms to the curvature of both top and bottom halves of the shell.
The bottom portion of the wall is visible when opening the water heater access door.
Eliminating, or even reducing the structural integrity does not appear to be a prudent move IMHO.
As John & Sandy M. mentioned, the weight
of the A/C unit is supported by that wall. In addition, the overhead cabinets and their contents also are supported by that wall. The need for the wall to be supported by the entire side of your TT tells me that the load it bears would distort the shell if only the top half were contacted.
Please consider all the ramifications before taking a step which may be very difficult to reverse.
Know all the facts about someone elses "apparent" success, so you can avoid any pitfalls. How has the modification stood the test of time, did the roof support an A/C unit and/or overhead cabinets, etc?
My feeling is, if the mod could possibly affect the integrity of the TT in a negative manner, it's not worth the possible short term benefits.
Enjoy the process, but beware the errors,
& Ann K.