Crit multiplier, extra damage on top of static bonuses, crit chance, etc.
Really, you want to say all those things make no difference? Even the armor ones matter after awhile because having enough to survive an alpha strike means the difference between being CC'ed for the first few rounds or being able to shrug it off.
Some skills are essential to the build. For example if you don't use two weapon fighting or Two handed weapon skill... It is useless to even bother using those.
But I will say the ones for Scoundrel, Warfare, Hydrosophy, Necromancy, and the like... Do feel kind of gamey in a manner of speaking...
It would be one thing if they just improved that school or made you better within that school...
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Also no... You never can just "shrug it off" from an alpha strike :P