and, lastly need some figures for understanding them in detail, namely,
1. ROF for Short and Long Bows, Crossbows, Slings and Darts
2. Base Damage
3. No. of Attacks per round for each of them.
ROF typically means "rate of fire", which in BG-terms is equivalent to attacks per round, which in turn is often simply called APR. As has been mentioned previously by other posters, slings and crossbows have a base APR of 1, all bows and throwing daggers have a base APR of 2, and darts have a base APR of 3.
On top of this, warriors get a bonus 0.5 APR at levels 7 and 13, investing two proficiency points in a weapon nets another bonus 0.5 APR, and finally the "true grandmastery" mod makes the full five point investment in a weapon type give an additional 1 APR. One more thing to notice is that the shortbow Tuigan and Light Crossbow of Speed both add +1 APR, meaning that the LCoS has a base APR of 2 and Tuigan has a base APR of 3.
Final thing to consider is that your APR cannot go above 5 unless you're using the HLA (Greater) Whirlwind or the mage spell Improved Haste.
So to summarize, a level 13 warrior with specialization in a weapon type would have +1.5 APR with said weapon type. Said warrior with "true grandmastery" in a weapon type would have +2.5 APR. A level 13 warrior with "true grandmastery" in crossbows would thus do 3.5 attacks with a normal crossbow and 4.5 attacks with the Light Crossbow of Speed. With "true grandmastery" in shortbows and using Tuigan, the same character would reach an APR of 5.5 and lose half an attack per round due to the APR cap.
As far as base damage is concerned, bullets do 1d4, arrows do 1d6, bolts do 1d8, normal throwing daggers do 1d4 +1, and darts do 1d3. Normal missiles thus aren't very good at all, no matter the weapon. It didn't matter too much in BG1 because enemies never had the health to survive all that many hits anyway, but in BG2 it's a different story. There are some things to consider, however.
Arrows of dispelling: These arrows cast "dispel magic" on hit. That's not bad.
Acid arrows: These arrows do acid damage with no save and count as +1 weapons, as far as I can tell.
Bolt of lightning: These bolts do 1d8 base damage + 4d4 lightning damage (with a save for half damage), meaning at least 1d8 + 2d4 damage. That's quite decent.
Kuo-Toa bolt: These do 2d6 damage + stun on a failed save. That's also quite decent.
Boomerang Dagger: A returning throwing dagger that does 2d4 +2 damage and is available in Chapter 2.
Fire Tooth (not to be confused with the ToB crossbow Firetooth): A returning throwing dagger that does 2d4 +3 +1d2 fire damage. An insanely good ranged weapon for mages. Not available before the Underdark, though.
Final thing to comment on would be strength bonuses. I'm not entirely sure here, as I've never done any serious testing (so someone please correct me if I'm wrong), but I *believe* all throwing hammers (essentially meaning the Dwarven Thrower), throwing axes (including, IIRC, no less that three different returning axes), Fire Tooth, Boomerang Dagger, and the Sling of Seeking include the strength bonus to damage.
Just come to think of it, by the way, but I do think your Fire Tooth and Boomerang Dagger may look a bit differently, since the Fixpack includes what I can only describe as an optional nerf to these two weapons.
- If I equip a dart I can still wear a buckler on my off hand. This is the only missile weapon that allows a shield.
So, what are your opinions about Darts in the long run for TOB? Is it good?
Slings, daggers, and darts are all one-handed ranged weapons, as are throwing axes and throwing hammers. You can use a shield off hand with any of these weapons, not just the darts. And, as HT has already said, darts blow big time in ToB. They just don't come close to doing enough damage.
Of course, this is a general complaint with ranged weapons in BG2 and moreso ToB. Even so, there's really no reason why the backline casters shouldn't have a ranged weapon to use between spells.
Take a cleric, for instance. They're not very good in melee because their APR is stuck at 1. But if you cast a few buffs, they'll end up with strength 25. Combine that with the Sling of Seeking and some +3 bullets. The bullets do 1d4 +4 damage, the sling adds +2, and strength adds +14. Total ads up to 21 - 24 damage. Won't hurt grunts much but hostile mages definitely don't want to be hit by that.