Lately some things have come up with regard to the 6.0 changes about spec identities, and I feel like some have forgotten that Brewmasters, Windwalkers, and Mistweavers are all Monks. Being part of a class comes with certain elements that you know are going to be there, regardless of which spec you choose. For example, Druids are naturey and change forms, Hunters shoot stuff and have a pet, Rogues are stealthy tricksters, and Warriors are big brutes that smash stuff. I'd like to take a moment and outline some things going way back to Blizzcon 2011 and all of the patches since then that define what the Monk class itself is about.
Themes
The official game guide page for the Monk class is a great starting place for the Monk themes. Monks are martial-arts fighters, kicking and punching their way to victory. Monks use their own inner energy, or chi, to fight. They do not rely on outside help, they harness their very being to do whatever it is that they need to do.
Monks are also heroes. All player characters in WoW are heroes in a way, but Monks fought themselves out of slavery with their own hands because they didn't even have weapons, they weren't just trained because it seemed like an efficient way to kill people. When it doesn't seem like they have anything, Monks are still able to fight. No one tells them what to do, there are no restrictions on what they can do. A Monk should be able to do anything he/she can imagine even if it doesn't seem possible.
The final theme isn't mentioned much in the Game Guide, but Monks are also about balance. They don't go overboard and don't get carried away. They do exactly what is needed, no more and no less. They weave things together very fluidly and are the only class in the game that has an identity of truly being graceful. They are versatile and have immense amounts of control over everything they do. This is what makes them Monks and not just cold-blooded killing machines.
Themes in Gameplay Throughout the Class
Roll: Roll is the iconic Monk ability. It is something you see Monks doing often, and you can instantly tell that someone is a Monk when they roll. It embodies a lot of the big thematic elements of the class. You can Roll wherever you want to instead of being restricted to going straight to a target like Charge. You can Roll whenever you want to, two or three times in a row if you feel like it, cooldowns don't tell you what to do. Roll isn't about hitting people or healing people or even having anything to do with other people, you Roll because you can. It always goes the exact same distance, in the direction you pointed in, and a good Monk will know exactly where the Roll will end before it even begins. It is controlled, but also limitless, the pure embodiment of what it means to be a Monk.
Chi: The resource system for Monks competes even with Roll for being the single most iconic Monk thing, and for good reason. Chi is generated and then spent, then generated and spent again. Everyone that's experienced the chi system knows that metronome feeling of Jab/spend/Jab/spend/Jab/spend in a very precise manner. It is precise because that is not the only way to play with chi, you can also build more if you like and spend the chi in various amounts. Chi is fluid and feels like combining abilities, but like Roll it also gives you the freedom to do a lot of different things within the confines of a very simple system such that there is room for great skill as well as predictability. Chi is anything but chaotic, you get it in set amounts and you spend it in set amounts with no randomization (with the ugly exception of Soothing Mist which is going away). What you see with chi is what you get, which allows for a ton of control to let you play smarter rather than faster.
Drinks: Having its roots in Pandaren tradition, Monks like to drink tea and ale. It's hard to notice on the surface, but the Brews have a very strong balance and control metaphor going with them. TEB and Mana Tea are cyclical abilities that give a pattern to resource usage, while Elusive Brew has its own cycle independent of anything else where it's not really a cooldown but more of a very slow metronome with its near 50% uptime going on and off and on and off again. All of the Brews are something that is done regularly, but you don't ever have too much of at any one time. Keeping in step with the Monk themes, all of the Brews are easily controlled yet have great freedom. You use them when you want to, not when a timer says you have to like other cooldowns.
Damage and Healing: This goes strongly with the balance theme, but also has a lot of overtones regarding the Monks' self-reliance and heroic qualities. Monks always do both damage and healing simultaneously. They do not have cooldowns that create large bursts of healing, nor do they have cooldowns that create large bursts of damage. No matter the spec, the "Chi" talents, Expel Harm (can be glyphed also), and Chi Torpedo always do both damage and healing no matter who they are used on. The only other class that shares this trait is the Priest class, everyone else has abilities that either do damage or healing or drain life, but do not both heal allies and do damage on a regular basis. While Priests have a duality theme going on alternating between light and dark, Monks have a balance theme in which both healing and damage are together and inseparable. You literally cannot play a Monk and not heal allies, and you can't play a Monk and not do damage.
What does this all mean?
Now that you've endured my ramblings on themes and such, we come to the point of the matter. Some things about the Monk class need to stay the way they are to still be Monk things, and others should probably change some to avoid feeling out of place in the Monk class. Even if you take game design out of the picture, from a purely artistic standpoint you can see some things that need to happen to make Monks feel like Monks.
Clash felt out of place in the Monk class as a clunky spell that is unclear, but more importantly it's too reliant on enemy positioning for the class that doesn't rely on anyone for anything, least of all movement or CC. Dizzying Haze is a great example of a spell that fits a spec's identity while also really being part of the class as a whole, it offers a lot of control and a lot of freedom while also just being about throwing barrels of beer at people.
Tigereye Brew must remain the cornerstone of the Windwalker spec (even if you don't like it) because Brews are a fundamental part of the Monk class, and downplaying it would just turn WW into a spec that doesn't really feel like a Monk because it would lose a lot of its control and flow. Fists of Fury really needed to change because it doesn't feel like it has the kind of self-reliance that Monks are supposed to have when it's dictated by outside factors most of the time.
Mistweavers need ReM and GotS to be less random because Monks are supposed to be about calm planning, not frantic button mashing hoping RNG blows your way. The spec as a whole also needs more control, a Monk should never feel helpless and need clever tricks to get out of a bad situation, Monks are more about planning in such a way that bad situations never even happen. Crane stance needs to be less restrictive because Monks aren't about restrictions, they're about having so much freedom that you have to make the right choices at the right times.
I'd like everyone to keep in mind that there are more than just gameplay reasons that go into designing a class or a spec, at some level the fantasy has to remain intact for it to still be interesting. What other themes do you think might be at the core of the Monk class or each spec? What changes might you want to see that would make the class feel more like what a Monk is really supposed to be about?