These have always been the problem with Monks since the beginning…lacking toughness and damage for the solo builds and not enough damage mitigation and healing for the support builds.
I am a die-hard fan of this class; totally enjoy everything about it but I am not blind to it’s deficiencies. I’ve just given up bringing it to anyone’s attention and hope that the powers that be would fix all the things that are wrong with Monks, or at the very least, make them not AS bad and not SO many. 
I’ve played this class since Day 1 and have seen all the changes made to it, some good and some bad. With the solo builds, I really enjoyed the time when they made changes to the R6 set and buffed Shenlong’s; that was the ONLY time Monks were able to compete on the solo leaderboards AND was the actual RGK in groups…then they introduced the Necromancer and needless to say, we lost that role quickly. Since then, we’ve lagged behind the other classes in clearing greater rifts solo and we still do to this day.
With the support builds, after all this time, I’ve noticed a pattern each and every time Monks were replaced by another class and have come to realize one undisputed fact: the zmonk’s healing and damage mitigation skills do not come close, nor can they compete to other classes’ skills that increase group damage. It happened when Crusaders were introduced to the game; they replaced Monks in the 4-man meta because they increased the group’s Critical Hit Damage. With the recent changes to Demon Hunters, they have now replaced Monks as support…I have to admit, I love Multishot and those sentries. 
We all know what needs to be done for our solo builds; those issues have been brought up many times already…who knows? maybe next season they’ll listen.
With the support builds, there was only one thing I could think of to make them viable again, un-nerf Serenity/Ascension. When they added that cooldown to it, it rendered the skill useless. If a Monk has a high enough CDR, we gave permanent invulnerability to anyone close enough. I remember before they nerf’d this skill - not even lag could kill me! 
. This could really work well with the changes made to Squirt’s; both the TK and RGK don’t have to worry about losing it’s proc as long as the Monk is right next to them. I don’t know, I’m not very good at theocrafting, just offering suggestions…
I can’t really fault anyone in particular about what’s happening to this class. I guess it’s all part of balancing the classes, I’m hoping they’ll come back around to us eventually
I sometimes look at the communities I’m in and I could count the number of people playing Monks with one hand, most of the time, I’m the only one, LOL. But no matter what they do to this class, no matter how much they screw this class up, I love playing my Monk, I truly enjoy playing her… always have and always will. Sorry for the long post.