Piratez includes several different weapons which rely on throwing skill when you "shoot" them : black powder bombs and molotovs, bows, knives. I really like how it lets you use recruits who have a bad shooting accuracy. Even weaker ones can be bowwomen with unlimited ammo.
However, there is the issue that these weapons don't train the right stat... The standard experience system gives "shooting experience" when you hit a hostile target with any ranged weapon (either directly or with splash damage), and this increases firing accuracy, not throwing.
So my suggestion would be for Extended to modify the experience system accordingly.
1) Ranged weapons which rely more on "throwing" than "shooting" should give throwing experience when hitting a hostile, instead of shooting experience.
2) In this case it should still trigger secondary experience gains (TU, energy,..)
Such rules can be hard-coded, because it only triggers in games/mods that include such weapons.
Now, personnally I wouldn't stop there, but I know this gets far from vanilla...
3) Grenade/proxies explosions which hit a hostile would give throwing experience instead of shooting experience. And still provide secondary experience, like in 2)
4) Throwing random stuff would stop giving throwing experience once the character has reached the average stat of a hired soldier.
5) For equity, I would give "shooting experience" to soldiers who shoot at a hostile target (even if they miss) if their shooting accuracy is under-average. This should not trigger secondary experience gain, because it's too easy to abuse.