Aero is just a mess on trailers. They have things sticking out everywhere. Ladders, AC, vents, awnings, non flush windows, moldings; you name it; they are an absolute mess.
Then there is the flat back that tries to suck the trailer back from where it came from.
Just to give some an idea of how much of a mess these trailers really are:
I used to work on airplanes. One owner wanted a faster airplane. We took all the button head rivets off and installed flush mount rivets. About a 14 MPH gain just by installing flush mount rivets. :E
This is on a very aero clean airplane. Now go out and look at your trailer. See the problem here?
Airstream comes the closest but even they are miles away.
Like I said in another thread. We can design a very clean aero trailer but nobody would want to buy it or live in it.