When it comes to the actual trees,here is my vague guess on what they will be about.
Shado-pan: Easy to guess that this will be the windwalker and brewmaster shared one, I think this will be a more physical themed hero spec, maybe they will even include weapon animations for tiger palm, fists of fury and strike of the windlord, I’m not sure ehat gameplay changes will be present, but My guess is that they will affect mainly damage dealers, as those sre the abilities BrM and WWs have in common, so, tiger palm, rising sun kick, spinning crane kick, blackout kick.
Conduit of the celestials: Is hard to gauge which specs this one will affect, because celestials are part of all 3 specs, but as we have the windwalker and brewmaster one, the other 2 specs will be connected to mistweaver. There are two possibilities here, either the spec will change how the summon CDs work, maybe the word conduit here meaning that instead of summoning the celestial you would call their powers to you instead, or maybe it means that the spec will change to expand on the summoning aspect of the class, if the first case is true, my Guess is that this would be a windwalker and Mistweaver tree, but this could be the second case as well, and this also makes me think of the possibility of this being a Brm and MW tree, because historically Mistweavers and Brewmasters have been more connected with their celestials than Windwalkers.
Master of Harmony is another very generic term that could be connected with every spec, but I’m thinking this is a Chi oriented tree, maybe interscting with projectiles and long range moves and maybe adding range to moves that are melee, I’m willing to believe this is the WW and MW spec.
TL:DR the way i see it, I boil down the 3 hero specs to the following themes:
Shado-pan: Physical side of monks, martial prowess.
Master of Harmony: Balance, Chi usage.
Conduit of the Celestials: August celestials powers.