As we saw in the tournament, AAHT vs Luchs is a very close matchup. And how fast can the AAHT be fielded?
Imo the SdKfz 222 needs to be closer to the Luchs in firepower. They do have the same loadout afterall
Another quite radical option is to remove the fuel cost on call-ins and increase the manpower cost (yes, like CoH1).
This way everyone can tech, but still needs to save up a good manpower bank to use a call-in ability to augment his tech.
And to prevent abuse, limit call-ins to one at a time.