The more I think about it, the more the idea of knighthood being linked to mechs in the same way it's associated with horses in European culture makes sense.
I've also decided that mechs as a concept evolved out of powered armor, with armor getting bigger and bulkier slowly over time until it wasn't a person wearing a suit but a pilot driving a machine.
So I think I'll change the Commonthroat word for mech (currently translated as “limbed vehicle”) and give it a single morpheme that encompasses anything from bulkier powered armor to big stompy walking war crimes. The word for a mech pilot would either be identical to, or related to, the word for knight.
I also think a sharp distinction will be made between remotely controlled mechs such as those used by healers and the internally piloted mechs used by soldiers. Remote mechs are safer and can get microscopically small, but you lose some situational awareness and there's input lag. No big deal in most situations, but on the battlefield a fraction of a second can make all the difference and you can't afford to that loss of awareness.