So first I do agree that "micro" light vehicles have some... interesting characteristics, the only exception being perhaps the UC since its received the most recent reworks.
It's easier to just refer to the unit itself.
Because micro light vehicles; that's confusing for the sake of confusing and adds another layer of characteristics which is not needed for the game or discussions. There is no need to attempt to categorise the light vehicles into smaller subsets. It'll go crazy and we'd end up with a category micro-light but player-micro-heavy vehicles doctorinal transport self-repair category and even more and as you cited some exceptions too. Also a WC51 cannot be categorised with an M20 or a 222. To make things worse, we could even start categorising infantry like Shocks and Pgrens with CQB and other CQC units.
I'd still love seeing some replays and casts of the WC 51 in 2on2+, I genuinely haven't seen ANY at all and I've been maining OST and playing against all possible variations of USF for years and I have not faced a single WC51 but once in the week the commander was released. The WC51 looks good in excel and on paper, but it has no niche and it is superseded by other doctrines.