SC,
I agree on your views

As for slingers they need a boost in Morale IMHO (from "awful" to just "not good"

). Sling damage at 9 would be ok if their range and prec were at least decent and the slingers didn't run before shooting

..
Supply : you can mod a unit to consume additional supplies, command is #supplybonus with a negative number to increase consumption. It could be a way to represent the higher standard of supplies (food but also housing, repairs...) needed by elite units? Just an idea, maybe bad ..