Stun breaks on damage.
I never said "all of them" but a good deal of trees have core abilties with auto-crits or vastly improved cit chances. Not to mention that the AC'es/specs are better in general. Always a disclaimer for commando/merc but as I've told you before; I'm not arguing based on worse classes. I'm comparing "my" class to the AC'es/specs that currently are way ahead.
Turbulance auto-crits for TK sage. Turbulance can hit for around 7500.