[Squirrelloid]

Higher liability to friendly fire and inability to mass effectively: two reasons why the arbalest unit is bad that have already been identified.

Also: flaming arrows applies to crossbows but i'm reasonably sure it doesn't apply to arbalests. While the 'ap' bonus won't matter, this does make the weapons magical (+2 to avoid shields), and does add bonus fire damage. Just a little bit of magic makes crossbows much more effective than arbalests.