I think an extra attack at level 11 is too strong. The Monk was only 2 dpr behind the fighter and 5 dpr behind the rogue's conditional dpr. You're trying to give the Monk an extra 9.5 dpr with that extra attack. That's just too much.
I could see improving the level 6 Ki-Empowered Strike feature. Maybe at level 10, 11, or 12 your unarmed strikes gain the +1 magical property. Maybe it even increases to +2 at a higher level. This is pretty good even if it were a once per rest feature.
I don't think the Monk is inherently supposed to be on fighter, ranger, barbarian, or rogue level in dpr, but I do believe that if you WANT to play a pure dpr Monk, you should be able to build/customize one. I don't think Bracers of Striking exist in 5e, but I would certainly allow them.
Also, The Monk of Long Death may have the best 11th level feature of any class. Got caught in a nuclear blast that does 100d100 damage? 1 ki point as a free action and you get up and walk away with 1 hp.
I could see improving the level 6 Ki-Empowered Strike feature. Maybe at level 10, 11, or 12 your unarmed strikes gain the +1 magical property. Maybe it even increases to +2 at a higher level. This is pretty good even if it were a once per rest feature.
I don't think the Monk is inherently supposed to be on fighter, ranger, barbarian, or rogue level in dpr, but I do believe that if you WANT to play a pure dpr Monk, you should be able to build/customize one. I don't think Bracers of Striking exist in 5e, but I would certainly allow them.
Also, The Monk of Long Death may have the best 11th level feature of any class. Got caught in a nuclear blast that does 100d100 damage? 1 ki point as a free action and you get up and walk away with 1 hp.