In regards to the arrows/bolts having finite amounts.
True it is more realistic to have a finite amount of projectiles.
But on the other hand, in for an example the IE games, you never were in danger of running out of arrows, all you had to do was stock up on a bunch of them before going adventuring, and on your adventures, plenty of adversaries had bolts and arrows their corpses freely passed on to you.
So the factor of always having projectiles for your ranged classes ended up beeing, "did you remember to stock up, spending 2 min clicking between select arrow, buy, then back to select arrow". Which in my opinion was more of a hassle than immersion. Therefor I voted, infinite of nonmagical arrow, but finite amounts of magical arrows.