Ah just as I was about to log out and get some sleep I had an idea why improving the throwing weapons could be a useful game enhancement.
It stemmed from re reading this post in the limiting bow range thread:
Units throwing knives are primarily melee units, so they'll anyway rush forward to attack you in close combat. Doing so they get into range for throwing knives.
Enhanced throwing weapons could be useful as the AI becomes more intelligent. When the AI feels like its on the ropes, as it does sometimes currently, running away low HP units. It could begin its flee tactic, preferably sooner when its on the losing side of the battle or it is outnumbered in general, and try and wear your units down with its throwing weapons. Especially when they being to use units designed by the player, that might be high initiative as well, allowing them to get some free shots in at your military. Think of throwing spears, with their armour piercing pulling a clutch snipe on a key unit... Ergh...
I get annoyed when the AI sneaks damage in via throwing knifes on bandits (or my custom horsemen unit...), anything that riles me up in tactical battles would be a nice change. Could you imagine if the battle lasted to their second volley and they sniped off your weakened units who were cowering safely, ensured of their EXP and a nice little rest period. I'd be mad.
(This is different to archers as archers are typically easy to focus down on, and they have a hefty initiative penalty.)