
What MM does need is a better counter against it, AGI needs to work a lot better for this, or something needs to give in this scenario, but the damage is pretty fine considering the owrk involved in getting to those quality levels of it doing so, and the ability to block it easily.
However... things I see that make it unfair
1)It's teamup with melee makes BOTH of them OP, people are focusing on MM as being unfair because it's the new kid on the block, but the real problem here isn't that MM can hit you like that, it's that if you run to avoid being hit by MM you end up dying to 0def by the Melee, not really the Marksman. The Marksman is just to push you into the trap, if you don't take it, you get sniped, either way.
This is fixed by allowing the 0def to go away and towards something else, like perhaps that hit hitting AS IF you had 0def, but once he stops he should be back with his regular def, it's overpowered bullshit that will you get you PWNED by a misclick and is BIGGER than just this one problem.
2)You don't get 'in combat' until the first shot. This allows for someone strong enough to 1hko without being seen.
This can be avoided easily BY THE PLAYERS and does not necessarily need a fix. If your village has an external rim 45+ tiles in each direction you won't get sniped. If you build your village like AD with no external walls, prepare to be sniped easily by someone walking the streets.