Best archer units to have for AS?...also Thorakitai do seem some what vunerable

[Claudius]

My sole mercenary Kretan archer just had 488 kills vs Carthage. Overpowered if you ask me.

I never use Kretans in melee though unless I was absolutely forced so the retraining argument wouldn't affect me. Persian archer-spearman are dirt cheap with a huge AOR. That and their versatility is what makes em great if I'm playing Eastern faction.