I have never seen it being used, just like the arty.
Hows's it a problem?
I mean, you have also "never seen it win games" even though VonIvan literally popularised the doctrine by winning an entire series in a tournament using WC51 abuse, and it's one of the most popular picks in 1 v 1, especially vs OKW, and is only overshadowed by Recon Support.
The WC51 is wildly overperforming, but the rest of the doctrine is only so-so. I would prefer improving the rest of the doctrine and making the WC51 more reasonable. It can still be the best ultra light because it's doctrinal, but it shouldn't be this godlike.
As always, only the usual CODGUY-level extremists think that an M3 clown car with the best mobility in game and can garrison Cav Riflemen or regular Rifles for chasedown wipes, that doesn't cost fuel
, doesn't require screwing yourself over by going t1, arrives earlier and has no tech or CP requirements
, can cap
, can self-repair
, has free nitro boost, and a high dps MG which outranges infantry - apparently that's not wildly overperforming.
When you compare the Kubel, the m3, the UC, and the 221, you see a nice balance of unique strengths and weaknesses.
Kubel is cheap, mobile, and can cap, BUT Low dps, can't really fire on the move, and can't garrison squads or do much else.
M3 has good mobility, good damage and can garrison units for chasedown wipes, BUT costs fuel, requires the building of the extremely unattractive Sov T1, can't cap or self-repair.
UC has good damage and decent armour as well as useful upgrades, BUT can't garrison squads, upgrade locked behind tech, poor maneuverability, higher cost, can't cap.
221 has good mobility, good damage, and a good upgrade, BUT can't garrison squads, costs fuel, can't cap, and is tech-gated in terms of timing.