Most? It is mostly 1 or 2 mechanics per fight. E.g. Krosus has one mechanic for ranged, but also 1 only affecting melees. Star Augur melees gotta play every mechanic while ranged barely lose.
Right now ranged specs have higher dps potential than melees. If melees are supposed to deal with all mechanics melee dps would need a big buff.
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Stronger in what sense? Frost mage and Affli deal way more damage than all melees. And optimizing melee range to targets is a mechanic every melee gotta face. So actually this a mechanic you seem to ignore. Ranged dont have to, so they need other mechanics to keep them challanged.