IMO, 2 things have "broken" in monk.
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1stly, the toughness. Both barb and monk have 30% damage mitigation by default.
Technically speaking, monk should be WAY MORE tankier than barb since monk can stack extremely high AR (1400+) and decent armor (8000+).
However, in actual gameplay, monks experience difficulty in T5/T6 due to life drains like water.
I play barb with 50% lower AR than my monk but 50% higher armor than monk, I don't feel the life of my barb drains as fast as monk when it stands in the middle of poison/plague/fire/firechain etc.
So, I reckon the toughness of monk is "broken". I tried MoC/Intimidation + Resolve passive (virtually 65% damage mitigation), it still hurt sh*t.
Monk is okay with the damage. I mean the main character. My under-geared monk can do 18-20m damage from fire bell. It is fine with the damage I reckon.
Here comes the 2nd point, monks lack of macai. Macai is the trend now!!!
WD/Barb/DH are using many macais now. With macais + main char, they can deliver high damage per second in total, collectively.
Wiz, with mirror ball, the damage is 2-3 times more. As good as having macai.
Cru, need I say more, it's flagship char. Many gears allow 2-3 times or more attacks.
So, IMO, it's either
1) Blizz reduce the resource cost of burst damage skills (i.e. bell) or giving more high spirit generation gear (i.e. Band of the Rue Chambers ring etc).
Or
2) Give macai to monk (i.e. buff mystic ally).
Blizz needs to fix the toughness of monk first. IMO, this is very important.
Without this, doing T6 could be a difficult task for monk.
This is especially monk could be the one and only melee char in RoS now (barb can do WT/Seismic slam with macai doing melee or just keep leaping).
Then, Blizz needs to fix either skills or gears for monk.
Last but not least, I won't say monk is totally "broken".
One must remember, not all char can do T6.
Monk can do T4/T5 just fine. Just like most of the chars are doing now.
To do T6, you need specific gears. This applies to all chars as this is gear based game.
Those OP build need specific gear but there is NO specific gear for monk that allow us to do that.
saw a guys posted in this forums
http://us.battle.net/d3/en/forum/topic/12674900079 and one of the guys says he can do T6 see his profile
http://us.battle.net/d3/en/profile/Nicotho...350/hero/859091 gila gila geared very high toughness too

+759 Lightning resist is high? I have +1536 Poison resist. Problem is, I must stack all single resist AND STI to be able to do T6. Two of my passive skill.
Thanks for the correction.
Barb has Ancients to help them. The Ancients themselves do more damage than monk.