Now that the game is for the most part balanced the ranged exp being halfed is unnecessary. I'd motion that ranged units should get full exp at least for the overall ranking, i don't think they need more exp to level.

I think halved ranged exp is fine when there is no retaliation. Because you don't take any damage, it's easier to build the unit up to a high level.

I reckon that exp should reflect the risk, so any unit attacking another without any retaliation would receive half exp.

Full exp for pop killed when defending and when attacking someone that retaliates.

Double exp for enemies killed that have a bonus against you (e.g. ranged fighting melee units and Melee units fighting their nemesis (e.g. a Hvy Cav attacked by a Mace should get double exp for any Mace it kills). Because you kill half as many, this will even out.