May have missed a previous suggestion. What about framae for Germans? Not remotely complex; a framae is a fire-hardened all-wood javelin, sharpened on both ends. Used in melee and at range. Very famous among the proto-Germans, since they were extremely light of iron (having nearly no native made armor and using their iron reserves to make weapons for the wealthy, or to imitate Celtic swords and helmets for the very wealthy). Framae would be light, plentiful, and be able to be thrown a good distance with great speed, but wouldn't be exceedingly powerful in terms of damage (though fire-hardened wood is tougher than one might expect, so not 'weak', perse). Similar javelins were also used by Lusitanian tribes in Iberia, and some Caledonian and Irish tribes. In that same vein, I'd ask for a removal of 'German Mail'; Germanic tribes of the period, even if they could make it, were imitating Celtic designs, and would be using inferior local iron, though imitations seem less likely than just importing Celtic armor. In 268 BC, they wouldn't have much of a framework available for the crafting much mail locally. Some early Germanic swords would be great though, give Germanics a bit more of a unique look.
Again in that same stream of thought, mail wasn't proliferated so much among Celts outside of the upper bodies, and even then, there was still some reliance on scale (both iron and bronze), as well as chest discs and cuirass (Celtic cuirass was not realistically articulated like Hellenic or Roman cuirass though). Some variety among Celts in terms of armor would be kind of nice. There are also a lot of nifty swords and such that could be used, or Rhaetian axes and pila (Etruscan pila, technically).
Could Celtic helmets be accompanied with a neck torc? And, just, neck torcs alone (offering no protection, but a good asthetic on Celtic soldiers). They'd also be worn by higher ranking Germans who appear to have imitated Celts a lot of the time in their dress. Gold, silver, iron, or copper torcs would be nice. They wouldn't be worn by the levies, but practically all other Celtic soldiers would have a torc.
Slings, if ever they can be made. Would be nice to have Celts with slings; they certainly used them far more than bows (though some Celtic cultures, or related near-Celtic cultures, did use bows more than most other tribes, like Rhaetians, who had their own type of longbow).
Oh, and on a specific unit, Gaesatai. The name means 'spearman', supposedly because they were so excellent with their javelins or pila (Etruscan pila were used by Celts in the Alps), yet, the unit has no javelins. They really, really should have javelins. But, so should most Celtic soldiers. Just, Gaesatai, it's actually in the name.
Of Etruscan pila; they were essentially identical to the Iberian soliferum. It's more or less just a long, thin rod of metal with a head at the end. Would be nice to see, considering it'd help note that Roman pila weren't unique (their advancement there was the addition of wood weight; the piercing power of the weapon was not remotely unique and pila were used by various Italic people over time; Etruscans, Ligurians, Italic/Alpine Celts, etc.).