The low level skirmishers - akonkistai, toxotai etc. - and their damage are about right, imho. They´re able to cause tremendous loses among other poor quality troops but anyone who´s armoured with more than a linen cloth just cant be bothered with them.

As far as my (limited) historical knowledge goes, they never had any significant role in winning a battle if the other side had some of them, too. They were just a nuisance and the prelude to the actual battle.

And medium/elite skirmishers (balearic slingers, thacian peltastai, syrian archers etc.) DO hurt a phalanx from a frontal arc (i´m an avid mak/baktria player and lost tons of men to them at beginning of my EB career ).

just my two cents