Throwing is currently unbalanced and needs to be fixed. Bugs are there to be squashed, not to be ported to other game modes.
Then again I quite like it. Javelins(if I don't confuse them with anything else) are meant to be thrown anyway. We could also have dwarves throwing down rocks and other dangerous stuff from the walls onto hapless enemies below. However I doubt they would cause more penetration. Even a flung Javelin won't be stronger then a crossbow bolt. Stronger then an arrow, possibly, then a crossbow, no. I think throwing should be a relatively easy to learn skill, allowing us, when time comes, to equip our melee forces with Javelins and melee weaponry, and have them throw them prior to charging into battle.
Btw, throwing is already used in tantrums, flying doors/beds ain't nice.