As title.
Make a throwing property, a new feat called "throw" where you can throw anything in your inventory.
In PnP "throwing weapons" actually are usually statted up as a minor melee weapon most times and have a range that you can throw them - handaxes, daggers, clubs are all ranged weapons by choice.
So do the same on Arelith. Take all current clunky, weird vibeless throwing things like shuriken, throwing axe, dart.
Add them as a property to the native weapon (like dagger) and just make a feat that does something along the lines of what a gonne does (a ranged touch attack). Convert shuriken into a small 1d2 dagger type item / darts also if you feel like not lumping them into everything.
I have no guideline of what damage and other things look like but I'll just give some shower-thought examples of what you could do. .
The damage for heavier throwing weapons should be balanced around something that feels like gonne damage but maybe not so high (so instead of the 60-100 range maybe like something like 30-40 average damage) when thrown.
Lighter weapons might do a bit of damage but something related to their historical purpose - so like a shuriken might only do like 10-20 damage but it also adds a bleed damage tick and other debilitations.
Let people basically throw anything but if it doesn't have a throwing property it just is unwieldy or dangerous.
tl:dr
* Make a "throwing property" & throwing feat (that everyone has)
* Remove current throwing clunky weapons, replace them for players by putting this as an item property.
* Now you can do things like add javelins and chakrams to the game but have them as "normal weapons" that also can be thrown just like IRL and PnP. 
* Weapon focus feats are the only thing that applies to how good you are at throwing that specific item. So if you have one handed edge and throw a dagger... you get bonuses for it.
* Let throwing interact with other feats for penalties/bonuses like point blank shot and called shot.
* Make thrown weapons be findable on corpses - and basically when you use them you have a good chance to retrieve - meaning you might keep a few basic daggers or whatever on your person just for throwing.
* Consider adding a "Returning" property for a few magical examples.
* Ogres and Firbolgs can now fulfill their blood destiny and throw rocks.