Yes you do have to give an actual argument for it if you start claiming someone else is wrong. Your optical stress idea also doesn't make much sense, not least since you undermine yourself by saying m43 is an exception - btw as far as I know almost all lenses designed for digital are telecentric, but this is because digital sensors without microlenses do badly with acute angles of incidence, and telecentric lenses give a more perpendicular angle to the sensor, it has nothing to do with aspect ratio (since lenses cast image circles, not oblongs). No doubt making precision optics at a smaller scale is harder, but this isn't the argument you're trying to make.
I don't know enough about lens manufacture to comment on your statement about certain lengths, but I do know that equivalent lenses (no matter the format) generally have similar designs; take for example how a 50mm Zeiss planar made for 35mm film uses the same optic formula as the (equivalent) 80mm Zeiss planar for medium format, yet you'll never find an 80mm planar for 35mm film.
You must be wilfully misunderstanding me because I'm making myself very clear: I'm not saying there is no difference, I'm saying the difference is in PERFORMANCE, not a special "look" due to some kind of unique DOF and framing properties FF sensors achieve and other sensors cannot.
This is a pretty good explanation of equivalence:
http://www.josephjamesphotography.com/equivalence/#6
Do you get it? I'm not saying your FF sensor isn't worth paying extra for or isn't better in certain ways, I'm saying that you can achieve the same DOF and FOV with a smaller (or larger) sensor by using an equivalent lens.