Part 1 of this wish:
We need the Sd Kfz 7.
Here is the Sd Kfz 7/1, the primary version I think we need most:

This is the same gun as on the Wirbl right now, only without the PANZER strength chassis and the hard-to-kill nature. Essentially it's soft-skinned and can be strafed down with MG fire, like an M3 currently.
This same halftrack frame was quite popular, and over 12,000 were made in all differing forms.
Here is the version that had a 37mm gun (same as the Ostwind, but without the panzer chassis):

Here is the troop transport version:

Note that it is towing a 88mm flak gun, for possible future AH inclusion.
Here is the transport version:

The vehicle reportedly runs 50kmh but other than that I don't know the details.
WHY WE NEED IT: Wish part #2: Perk the Wirble. Perk the ostwind. Whatever you perk them, make the wirb 1.5x whatever the perk on the osty is. So if the osty is a mere 5 perks, make the wirb 10 perks cost.
Addition to make it even better: Wish part #3: Add a reload delay. The player doesn't need to do anything! Just like firing a tank gun, you have to wait x seconds. Make it so you fire 20 rounds and have to wait 2 seconds (a ready crew standing right there waiting to reload the magazines, pop out the old, slide in the new, shouldn't take long).
[EDIT: These guns had stick-mags like a BAR rifle that had only 20 rounds in them, they had people standing by to change them repeatedly, and only fired 2 guns while the other 2 were being readied under most conditions] This may or may not be implemented into other things such as aircraft later on, but it is especially needed in the wirb and in the proposed Sd Kfz 7/1 with the same quad gun.
The player can keep holding the trigger down if he/she wants, just like in a sherman. They just have to wait for the reload before the next round(s) leaves the barrel.
This would give us another soft-skin vehicle like the M3 that would double as a flak (2 kinds of flak, even!), yet still run supplies and troops. It also might be interesting to see the troops leaving the benches instead of jumping out the back. It also paves the way for the much-wished-for towed mannable 88mm flak position in the future!