Hi,
my intention is to make the scenery as slim as possible.
Drawcalls can be reduced dramatically with MCX and I don't see a disadvantage there.
The AC3D jobs remove errors in the drawing, mainly duplicate vertices.
In the meantime I had some cases, where surfaces dissappeared after surface optimization.
So you may skip this point, but have to take into account, that there are irregular faces in the 3D object.