then there's also the question of what benefit they'd ultimately add to the game. From the most pragmatic standpoint possible...
They give our characters option to fight when regular way is not possible for some reason.
For example Druid ...
Druid Cantrips have only 8m range in BG-3.
Druids are profficient with: clubs, daggers, darts, javelins, maces, quarterstaffs, scimitars, sickles, slings, spears
Meaning if you cant use Cantrip and dont want to spend your spellslot, your druid is litteraly useless unless Slings, Darts, or Javelins are implemented.
That is pure pragmatic reason ...
Then there are others, sometimes coventient excuses, like: immersion, freedom of choice, and also options ... players usualy love to have options.
Honestly, given how magical ammo is implemented in the game (D:OS-style rare arrows that work for both bows and crossbows and are more about utility than extra damage), unless there's going to be a big revamp of the the whole mechanic (separate ammunition types, finite regular ammo) in the future, it's very unlikely that there will be a whole third weapon type for which there needs to be a different kind of missiles (having slings launch arrows will be incredibly dumb). Plus, I don't think there were any datamined models found for either slings or darts, although if Grymforge is anything to go by, there isn't quite everything equipment-related in the files just yet.
I dont think there needs to be some huge mechanic rewamp, or special amunition type for every single weapon ...
If they would keep arrows as they are now (wich i hope they dont, even tho i probably hope for different changes) it only means that if you will be using Slingshot, Blowguns, or Darts, you will not use those arrows, nothing more.
I cam quite easily imagine that Darts will work like yet another throwing weapons, just like bombs, smokepowder satchels, or the vial of some fluid ...
Then all Larian need to do is reduce range for throwing (of everything except those Darts) by half for example, wich they should do in my opinion anyway ... and implement Sling as item that double your throwing range (again, except Darts, yes im aware it would mean that you would be able to shoot your boots through it, but i dont think its necesarily wrong).
Im trying to say that let us not make premature conclusions.
Either that, Druids and Wizard had this profifiency was just a placeholder ...
Or that Sorceres dont have them is just oversight ...
Chances in my opinion are 50/50.
