Myrrh, Frankincense, and Steel: Kurald Galain's Guide to the Magus

[Kurald Galain]

You treated the various energy enhancements (flaming, frost, shock, etc.) as stackable, but to quote Pathfinder Core Rulebook, pg 470 (and again, forgive me for rules lawyering) "Upon command, a flaming weapon is sheathed in fire... The effect remains until another command is given"

By my reading, this means "if you speak the word 'fire' in Elvish, a flaming weapon is sheathed in fire... the effect remains until you speak the word 'ash' in Elvish." And likewise, "if you speak the word 'lightning' in Dwarvish, a shock weapon is covered in electricity..."

It shouldn't be read as "... the effect remains until you speak any other command word whatsoever".

Then why doesn't anyone mention abusing the f--k out of this with a soulknife?

Because this isn't abuse. Rather, it is the arcane equivalent of power attack. A level-5 Magus (or soulknife) has the choice of making a weapon +2 to hit / +2 damage, or +1 to hit / +4.5 damage (i.e. 1d6+1), or +0 to hit / +7 damage (2d6). In other words, drop to-hit by two points to gain +5 damage, which is pretty much the same returns that power attack gives you. Useful and versatile, certainly, but not at all abusive.