The tension design is imo not that inaccurate for the Spartans and Athenians, they seem more focused on an earlier time frame.
Now for the Hellenistic civs it would be (BTW i just noticed the Seleucids seem to have no bolt shooting artillery).
Polybolos is already in game, but only for Ptolemies.
I'm not sure every civ should have the ability.
But at least the civs that actually captured them historically could have a technology to unlock siege engines.
https://tyche.univie.ac.at/index.php/tyche/article/view/5047
This article at least argues for them being Scorpions but the original source is no that clear in any case.
German mounted units seem to have incorrect composite words, it be more correct to use
Skeutaridjô (for Javelin)
Gaisaridjô (for spear cavalry)
Aþalaridjô (for champion)
Although if the Javelin Cavalry is really supposed to be Helvetian it might be better to call it Walharidjô (Celtic/foreign rider) or use a Celtic name.
They were used alongside more complex siege engines.
Maybe could be an option available at phase 2.
I think at least more civs without siege towers or catapults could have them.
Perhaps it could be implemented for more units.
I think most ranged units could have a weak melee attack like in AOE3.
Thureophoroi, Hastati, German spearmen, Celtic spearmen, Iberian infantry, could throw a single spear before melee.
This distinction might be partially due to gameplay limitations, i'm not sure weapon switching was implemented yet.
So ranged and melee ships are separated.
Gauls dont seem to have used bows that much until later in gallic wars.
For Cimbrian celtic allies i'd have
Volcae Swordsman
Tigurini (helvetian) Spearman
Maybe also Toygeni (helvetian) slinger if you really want a ranged unit.
EB2 Helvetian spearman
https://europabarbarorum.fandom.com/wiki/Gaisoualos_(Helvetii_Phalanx)