That is what i was thinking, yes.

This unit has been removed from the Britons due to a lack of historical accuracy. No zweihander.

Spartans have an elite swordsman, they were the precedent. Carthaginians, Romans and Seleucids all have advanced infantry swordsmen in their rosters. I don't think it's an issue, but perhaps it's better to give them a swordsman champion? One with a weapon similar to the famous Zweihander, just to be cheeky.  EDIT: See https://riseofnations.fandom.com/wiki/Solduri

Sure but why the Germans should have elite swordsmen and other civs not?  It is the comparison and the coherence across the different rosters I am referring to. 

''Military colony'' type building? And maybe the citizens you train there can build a few more of the Lusitanian/Celtiberian buildings

There might be enough justification for a heavier elite infantry. It is not described what weapons they had; but swords are possible. We know the Cimbrian cavalry used swords. But also the women of the Ambrones, so they don't seem to be only for cavalry.  

We worked on some of this in historical and can continue to do more if you think it's necessary! @TheCJ