My take is that fast GVs add more tactical variety than slow big gunned tanks which tend to make the fight slow in pace. A relatively fast GV with ability to be dangerous to any tank from rear quarters would make it dangerous to stay camping in one spot. Of course a big caliber always has certain appeal but would it be "good for the game"?
And the point here is not to add something German in other sense than just that 234 already has similar GV in allied inventory and typically the scenarios are about Germany against allied nations, so it has a place there, and if the rival is Japan they are usually naval engagements so there is no need for axis armoured car. In MA environment it serves as an upgrade from M8.
-C+