E.g. allowing both 1x1 and 2x2 armors on the same soldier type makes little sense; and such things will be disabled for common benefit.
But how else could you make Space Marines wear both standard Aquila and a Terminator Armour, for example? Have a separate marine type for the Terminator? Could work, but it would be kinda weird.
And the same applies to
Piratez. There's the old idea of biker gals, using 2x2 motorcycles to move around. And even excluding that, 2x2 armours have been planned for a very long time, there are just various technical problems to solve first (like custom moving sound for said bikes).
In
X-Com Files, I plan to turn all HWPs to soldier types, so you could have an "AI core" which can be installed into various "armours" - a standard HWP, a small drone, and so on. These units also vary in size.
All I want to say is that it appears an important feature for pretty much all mods using OXCE+, so I don't think it can be ignored. I understand it is problematic though...