I don't think that it is correct in the end to call Yakhmar a caster or ranged favourable fight.
It's an AoE fight, but adds when spawned very bunched up are so close that I think melees aswell can do very high DPS.
In most of the tries we had ToSes were doing the highest damage, but was fun to notice that for the first and only kill we had a barb was doing most of the damage .
It was a non optimized try, most classes had still to tune properly builds and rotations, but DPS was high enough with a decent margin to kill adds in time, so this says what for example barbs aswell can do on this fight.
It's more a matter of position that raw DPS, so I consider it more a tactic fight than a pure DPS race / gear check.