It does not mean Kubel problems should be ignored.
You can compare exactly to Brits. Infantry Section combo with UC. That is great AI stacked faction. I do not see the issue in fixing Kubel which it currently experiences. Could one counterclaim this as an issue also, vice versa?
OKW does have access to good AI units but it does not mean that Kubel should remain the way it is being lackluster.
It needs to do more as a support unit. Compare it to UC which is perfect as a support unit. It should least meet its standards of being able to support or have good DPS which it is currently lacking. Have an MG upgrade option would be good. Change vet 1 ability as "Detection" is considered OP for more combat effectiveness.
Why would anyone pick Kubel as it currently is. Definitely not 1v1 and most certainly not any higher. Pros even can elaborate that fact. Kubel should be a glass canon. Strong damage output but weak as it currently is. That should not be a problem for allies to counter it at all.
Kubel should not be a derelict choice if it is there. If no changes are made, then I suggest replacing it with another unit if nobody wants to see it changed!.
UC is 50mp more (volks and penals cost difference) that's why it's better in combat. It's also UKFs anti garrison tool.
The combo of UC and Tommy is pretty good, but not nearly as synergistic as sturms and a Kuble. If a UC takes damage it needs to spend muni to repair or wait until sappers hit the field. UC and tommies also puts UKF on the back foot for map control. Follow up infantry are also more expensive. UC is also significantly slower than a Kuble.
Adjust the Kuble vet so it can earn it and see where that goes. Full on overhaul very well might not be needed. You want it to suppress? That's in its vet! So is self heal.
You really need to stop comparing it to the UC though. It's a more expensive unit designed to augment the UKFs lack of field control and their initial bleed. It's a strong fighter because it's designed to. That's it. It can't scout and it doesn't cap..
Players do build it. I build it and I see it alot in team games because it allows 1 unit to do the back capping of multiple players and still catch up in time to contribute to the initial fight. I've also used it to get behind that pesky starting vickers and pushing off the first unit they built.
Putting more AI into the okw starting will make it overbearing and impossible to play against with 2 shock units. Sturms as it is can already dominate the start of the game, let alone with a no bleed, fast, murder machine in tow.