I am most excited about playing the monk of all the classes (but that's a story for another post). However, some of the ki powers struck me as underwhelming (especially the entry feat) so I figured I'd look at the other path into an wise-master monk build; namely multi-classing cleric.
So here is what we will do. We'll build a monk that take all available ki powers as soon as possible, and compare it to a monk that takes all Cleric multi-class feats. I'm going to ignore magic items, skill and general feats because I can only spelunk so much rulebook in one day :)
First both monks will be of no specific race, with stats focusing on Dex > Wis > Con. The monk/cleric will try to reproduce ki powers with spells This is because I don't want to be stuck comparing very different things, like teleportation vs finger of death... The assumption is that you are a player that thinks the ki powers are cool and wants to use them.
str 12
dex 18
con 12
int 10
wis 16
cha 10
Ki-mystic
Level: effect
1: open feat
2: Ki Strike (ki = 3)
4: Wholeness of body (ki = 5)
5: +2 wis (ki = 6)
6: Ki blast (ki = 8)
8: Wild wind stance (ki = 9)
10: Wind jump, +1 wis (ki = 11)
12: Abundant Step there is no level 12 ki power, so we are taking the 2nd level 6 one (ki = 13)
14: Wild winds gust (ki = 15)
15: +1 wis (ki = 16)
16: Quivering Palm (ki = 18)
18: Empty body (Ki 20)
20: open feat
For the monk/cleric spells I'll note which spell is usually prepared. Remember that the multi-class archetype gives you access to the whole common divine spell list.
Monk/Cleric
Level: effect
1: open feat
2: Cleric Dedication
4: Basic Cleric Spellcasting
5: +2 Wis
6: Domain (fire) (sp = 4)
8: Divine Breadth
10: +1 Wis, open feat
12: Expert Cleric Spellcasting
14: Advanced Dogma (Advanced Domain: fire)(sp = 5)
15: +1 wis
16: open feat (sp = 7)
18: Master Cleric Spellcasting
20: open feat
Spells prepared at various levels
Cantrips: Shield, Guidance
4: Heal
6: Heal, sound burst
8: Heal x2, sound burst, L3-Heal
10: Heal x2, sound burst, L3-Heal
12: Heal x2, sound burst x2, L3-Heal, air walk
14: Heal x2, sound burst x2, L3-Heal, air walk, flame strike
16: Heal x2, sound burst x2, L3-Heal x2, air walk, flame strike, Blade Barrier
18: Heal x2, sound burst x2, L3-Heal x2, air walk, L5-sound burst, flame strike, Blade Barrier, Finger of death
20: there is no level 20 ki feat, so I'll stop here.
Comparison
Now let's compare the ki powers to the spells.
Level 2
It's hard to say how strong ki-strike is, but +1 to hit is valuable. There is no equivalent cantrip, but shield is similar in that it swings the RNG in your favor by one point. Call this a slight edge to ki-mystic since the cleric has to deal with an anathema.
Level 4
Now, both the cleric and ki-mystic get to cast heal 1/day for 1d8+wis hp. The cleric can target allies but the monk does not provoke. However the cleric spell does not eat into his ability to use shield and the monk only gets 1 ki strike in a day when he heals himself. The monk can use his healing to remove poisons. We'll call that a wash
Level 6
Now we're talking. The ki-mystic gets ki-blast which deals 4d4 (10) force damage in a 30 ft cone. and his heal heals him for 3d8+Wis. He can use these two powers in any combination 4 times. The cleric gets sound burst which deals 2d8 (9) damage in a smaller area but its not a cone so it more precise. Still, significant advantage to the ki-mystic.
Level 8
Wild wind stance seems pretty lame... It also only increases your ki pool by 1 instead of 2 like every other ki power. It seems to me that wild wind stance is just worse then using shuriken. It has 30ft range instead of 20, but no range increments and only adds half your strength. Ignoring screening is nice, but doesn't fire the imagination. The ki mystic can use his heal and ki-blast 4 times in total, and wild wind stance once. His heal heals for 5d8+wis and the ki blast deals 6d4 (15) force damage.
The cleric at this point learns the fire domain, and can shoot a ray for 4d6+wis (18) damage 4 times per day. Considering that the most a wind stance attack can do (with a +5 etching) is 5d4+strength that's kinda sad.
The cleric can also heal for once per day for 5d8+wis, but has to spend 2 actions and provoke to do so. Overall, this level still goes to the ki-mystic.
Level 10
Not much to say here. Numbers go up a bit, but there is no new spell level. The cleric is sad. He can give people fire resistance now...
The ki-mystic gets wind jump, which is kind-of a budget fly, but that's cool. Also +2 ki.
Level 12
The Ki mystic picks up abundant step, because there is no level 12 ki-power. Abundant step is kinda lame, its a line-of-sight teleport with 10-20 ft range. It is doubtless useful for crossing hazards and makes for a cool visual, but is not that exciting. The cleric gets air walk and can target his friends with it. That's strictly better then wind step. Plus another sound burst.
Level 14
Ki mystic gets wild winds gust. Which lets him attack everyone in a 30ft cone while in wild winds style. That means you need to spent 1 ki to enter the stance, and 2 ki to use the ability. Except wild wind stance sucks... Even with a +5 weapon, you are only hitting for 5d4+1/2 strength. Ki blast costs less ki and deals 8d4 (20) force damage. We only really take it for 2 more ki points. The ki mystic has 15 ki points which is 7 casting of ki-blast or wholeness of body.
The cleric gets flame strike which hits for 8d6 (28) but can be more easily targeted, letting him hit creatures that are more then 30 ft away.
Level 16+
The monk gains quivering palm, which strikes me as a very awkward ability. You have to be in touch range, spend two actions -- potentially provoking -- and hit your target. Then you have to spend another action to trigger the palm. If they pass their save, your whole 3 actions are wasted. Otherwise they are stunned for 1 round... (or die on a crit fail). That seems like a lot of effort when you can just use stunning fist.
Empty body is pretty cool, but not level 18 power cool. I don't know what you can use eternalness for other then scouting things. Can you punch people with a ghost-touch gauntlet or something?
The cleric gets neat spells (including ethereal jaunt) but arguing that "Its better at level 16+" is sort of silly...
Conclusions
When I started writing this post, I thought the cleric would win hands-down... But I guess I was wrong :) Now, this says nothing about what the cleric could do differently from the ki-monk or if damage is useful. Just that the monk's ki powers keep up with his thing: providing superior healing and damage to the cleric.
I do think that the ki powers from level 8 onward are unexciting. I don't see myself using them for much because they seem outclassed by ki-blast, wholeness of body and the spells that you gain at those levels. Unfortunately there is no way to focus on lower-level ki powers or to expand your ki-pool except by taking powers you don't really want. This means that it is hard to diversify your ki-based build. Maybe there could be a feat to reduce the ki cost of a lower level power? The higher level powers also need to be more different and there needs to be an extra ki feat that, gives you +4 ki or doubles your pool or something like that.
Getting nothing at level 10 from your spell-casting multiclass feels bad. Maybe divine breadth should give you another cantrip or something at that level?
An interesting consequence of multi-class archetypes is that all class feats must be balanced against spells since everyone has access to 8th level spell casting if they want.
P.S. Ki strike is still lame.
Discuss
I may do a wizard multi-class build to see if that can keep up with blasting...
If you MC Cleric, go with the Nature domain for Spike Thorns or whatever that domain is - +1 damage on unarmed strikes and against melee attackers seems pretty good.