Most "Marksmen" kits are fine except for a few, they were designed to fit a class that was "supposed" to counter Fatties by constantly dodging/moving while hitting many autos and to have enough tools to just give them a chance to avoid their squishy counters.
The real problem is Crit + Attack speed synergy a.k.a BpS, it is what allowed "Marksmen" to not bother dodging/moving and just stand still to draintank Fatties and also allowed them to kill their squishy counters more reliably and faster than they could kill them.
BpS is what broke "Marksmen" and their kits ( and in turn, broke other classes and their items too ), not vice versa.