I was looking up some stuff on Tai Chi and started thinking about ways to base monk abilities on different martial arts. I'm not exactly an expert, so I'd appreciate any suggestions. Mostly I'm just going by Wikipedia and a few observations.
General monk stuff:
Can walk on vertical surfaces at lv3, water at lv4, and air at lv5, as long as they end their movement solidly supported. At double these levels (6, 8 and 10) they may use these abilities for indefinite periods.
I'd say scrap the level 3-5 abilities. As soon as you added the part about ending movement solidly supported I think it should simply be reworded. Make level 3 (vertical) the ability to climb at base speed with no penalty. Level 4 (water) should either be balance or jump -- Balance = no penalty for moving normal speed; Jump = always considered as running start. Level is simply a jump check reflavored to be a jump in a straight line rather than the jump being in an arc.
I haven't run the numbers, but as long as someone that maxes ranks on the appropriate skill can usually make the check (over 50% if there are no circumstantial penalties) it would be a better design element.
Levels 6, 8, and 10 I'd so something similar with skill checks. But, I'm okay with allowing it to happen for indefinite periods at will also. (I also had the thought to write the ability to say something like "if your ranks in the relevant skill equals or exceeds your level, you can do this indefinitely", but something doesn't sit right for that one.)
Baguazhang (Eight Trigram Fist, "Airbending" + "Gentle Fist")
You do not provoke an attack of opportunity for moving from one of an opponent's threatened squares to another.
Does this mean if the opponent threatens three squares I only don't provoke for moving out of the first/into the second, but if I move out of the second/into the third I do provoke? Either way it should just be cleared up a little bit. The way it reads now can be interpreted as moving out of one square only.
You could also simply make it a Tumble check. Something with a DC equal to the foe's CR.
If the path of your movement encloses any creature's position, you gain 20% concealment against that creature for 1 round.
Needs more definition. I think I know what you're saying. That shouldn't be "think I know".
Xingyiquan
For every two attacks with which you strike a creature in a round, you may force them back 5ft. You may then move 5ft forward if you wish.
For this last one add, "You're movement when doing this does not provoke attacks of opportunity from that foe," or "You're movement when doing this does not provoke attacks of opportunity."
I figure these abilities are sorted into order of strength, and you gain abilities from one school interwoven with lower-level abilities from others.
I was going to complain about getting all this at level 1. Talk about quite a level dip. But this last statement sounds like you simply haven't set up the level progression each ability is gained at. Overall pretty nice.