Mnk was not part of the meta during 3.4/3.5-ish for super fast fflogs speed runs, but still got spots in many farm even speed run pfs, .. casters had (and still have) way bigger trouble getting in farm pfs..

Sam can still remain top dps, just not by such a large margin... and don't forget, Sam still has the slashing Buff, so it will still be merit in farm pfs.