Is this "goofy sewer storage contraption" basically a length of 6" plastic pipe attached to an elbow and swivel joint (actually a toilet flange, I think) at one end and a screw-in cap tethered to the motorhome body on the other end? That's what I have on my (rather older) Coachmen Santara. It seems to work very nicely for me, and I've never had any trouble with it hitting/dragging. Some brands of sewer hose bayonet fittings are too big around to fit in the pipe, particularly if they have grip tabs or similar protrusions.
I don't think, at least on my motorhome, it hangs down below the axle and certainly doesn't impinge on the approach/departure angles. I suppose some very specific severe ground unevenness could apply pressure to it and damage things, but it would have to be very, very uneven ground...and rather unluckily arranged unevenness at that. I also can imagine that different models could have different clearance issues (or lack thereof); I have pretty decent ground clearance in general.