So I came across a homebrew archetype for Monk called Way Of The Lynx. The abilities at the higher levels are completely okay, but the one in question is the third level, Sneak Attack:
Starting at 3rd level, you have learned to exploit an enemy's distraction. Once per turn, you can deal an extra 2d6 damage to a creature you hit with a monk weapon attack so long as you have advantage on the attack roll. You don't need advantage on the attack roll if another enemy of the target is within 5 feet of it, that enemy isn't incapacitated, and you don't have disadvantage on the attack roll. At levels 5, 7, 9, 11, 13, 15, 17 and 19, this bonus damage increases by 1d6.
It follows the same ruling as the Rogue's sneak attack feature, with the same 1 d6 damage increase at the same levels as it does in rogue.
My question is would this be too overpowered combined with flurry of blows and extra attack granted as a Monk down the line?
And does it make sense for it to even be the feature of an archetype without it being watered down in some way?
Best Answer
There are different ways something can be (un)balanced.
By the numbers, this feature gives a class one archetype that massively boosts damage (doubling and tripling) compared to its other archetypes. Or, looked at another way, this feature basically creates a rogue with a lot more attacks. Either way, it's a strict increase in DPR. There are opportunity costs to taking this path, but I'm not even go into that because...
It's unbalanced in another, perhaps more-important way. The big problem isn't if this archetype does damage better than a rogue; the big problem is if this archetype rogues better than a rogue. This archetype takes the combat-signature of the rogue class--the ability to get in, deliver a powerful punch, and get out--and gives it to another class. Let's assume you never use ki to enact a Flurry of Blows, but rather use it always for Step of the Wind. At level 5 you can basically do this every round and so you've got Cunning Action as a choice. You've got the same sneak attack dice, you've got the same number of SA-qualifying attacks (assuming the rogue is two-weapon fighting to keep up with this monk's Extra Attack), and you've got unarmed strikes to dish out, too. In combat, at least, you've got the choice of being a more-deadly rogue. Who deflects missiles and slows falls and, by the way, can has a choice to use ki to stun their opponent rather than to emulate cunning action.
3.5 had tiers of classes. 5e has not manifested that in any significant way. This archetype establishes itself a tier above the others. And in no small part it's the choices that create that power.