Arkhandus said:
Crossbows can be used for improvised bashing in melee, but are technically ranged weapons by default. Ranged weapons cannot threaten an area.
Granted, that's what the rules say.
However, as was clarified before, you don't need to be proficient in a melee weapon to threaten an area with it. Thus, a human warrior armed with a chair (improvised weapon) threatens the same area as a human warrior armed with a longsword (non-improvised weapon). The first gentleman merely has a -4 on his attack roll because, as you point out, it's not really well-balanced, crafted, etc., for battle.
Now, the problem does not arise until someone - in this case, the DM - says, "Here's a new entry for the melee weapon table:
Crossbow, Light: Medium, Bashing, 1d4, 20 x2, Hardness 5, Hit Points 3.
These statistics reflect this weapon's use as a melee weapon. Proficiency
with this weapon does not apply when using it as a melee weapon, so a -4
attack penalty applies. Individuals may take an Exotic Weapon Proficiency
to use this weapon as a melee weapon to eliminate the non-proficiency
penalty. If the amount of melee damage inflicted by the weapon exceeds its
hardness rating, the weapon suffers damage equal to the excess."
For those wondering how such a strange situation occurred, our party crashed a frogman gathering on a lower-level of an EVIL TEMPLE (TM) that had been sunk into the swamp ages ago. We stumbled upon what appeared to be a meeting hall and, as our particular group was wont to do (I think we had three barbarians in the party) charged.
My wizard - the only one with an Int score higher than 12 - walked into the door and took a shot at one of the milling frogmen, probably downing it (I can't recall).
In panic and confusion the frogmen scattered, and a few ran past me to flee through the door behind me. Since the DM had just sent out the "Crossbow as Improvised Melee Weapon" guidelines, I asked to make an AoO on the fleeing frogman, with the results previously discussed. As I lacked a decent BAB, a positive Strength bonus, and proficiency with the weapon in question, I didn't think my chances of scoring a hit - or of exceeding the weapon's hardness should I successfully hit - were enough to worry about. It seemed like an opportune time to try out the new rules.
And there was much rejection.
Anyway, the discussion is certainly interesting.
EDIT: To add:
Basically, my problem with the ruling - and with the responses given on this board - is the following:
If I had shot my crossbow, dropped it, and pulled a dagger (proficient), I'd get an AoO.
If I had shot my crossbow, dropped it, and pulled a longsword (not proficient), I'd get an AoO.
If I had shot my crossbow, dropped it, and pulled a bust of Beethoven (as an improvised weapon), I'd get an AoO.
If I had shot my crossbow, dropped it, and pulled a ladder (as an improvised weapon), I'd get an AoO - and probably reach!
If I had shot my crossbow, dropped it, and pulled a crossbow-shaped piece of wood (as an improvised weapon), I'd get an AoO.
Since I didn't drop my crossbow, I don't get an AoO, even though it's still an improvised weapon.
So, that's basically the point at which I disagree.
Also, the rules allow you to mix melee and ranged attacks as part of your iterative attacks. Imagine a fighter with 3 attacks per round and a dagger in hand. He can stab with his dagger as his first attack, throw it as his second, quickdraw a sword, and slash with that as his third attack - provided he only takes a 5' step during that period.
Anyway, like I said, great discussion. Thanks!