JapanMS - Open-To-All Test Server; May 16th ~ 30th

Wrong.
No mage skill that's worth a damn requires a staff / wand, except for BaM skills, which you can't rebirth out of anyways.
No warrior skill that's worth a damn requires a sword / axe / mace / spear / PA, except for WK/Paladin charges. maybe DK Buster / Fury, and possibly Hero Intrepid Slash.

There are plenty of skills that require a specific weapon and cannot be used without it. Not just Paladin's Charges. Unless it's suddenly changed, the majority of attack skills require the class' specific weapon to be able to use, and therefore bothering with those skills with the intention of just re-birthing is foolish. There's also a good amount of buffs that won't work without the class' specific weapon either.