sweboz: germanic cuneus?

[Phalanx300]

I believe the Romans used wedges as well against Boudica.

And the Swine head formation or wedge formation was used by Germanics. I believe the Suebi formed multiple wedges against Ceasar?

[Ludens]

I believe the Romans used wedges as well against Boudica.

At the battle of Watling street. However, we don't know exactly how big these wedges were: whether it involved a few men or entire cohorts.

AFAIK the wedge formation is hardcoded to be for cavalry only. It's possible to designate the Germanic BG as cavalry, but that opens up another can of worms. Never mind that the interface allows for only one "special function" button on the interface (and generals get the rally special function automatically) and that the in-game effect of the wedge is questionable. So I am afraid I don't see how this would work.