Zen Sphere would have to be nerfed pretty dramatically to make it undesirable as part of our standard damage rotation. With my level 90 in PVP gear, RSK hits for ~105k unbuffed on average, while Zen Sphere ticks for ~37k, doing ~300k per cast. They'd have to nerf its damage by 67% just to make it go under RSK in the priority system, and nerf it by ~75% to make BoK 'better'. At that point, its a fairly impotent ability...

Some updates from the PTR:

Energy Regeneration is now 13 per second at base.
Zen Sphere still does enough single target damage to warrant being cast over all other abilities.
Chi is not lost when an ability is dodged or parried.

Yeah that energy regen has to be a bug. I'm at around 14.02 energy per second, and i feel i can't use it fast enough almost. I never can find the time to squeeze in fists of fury especially, without overcapping. I don't expect this energy regen to stay.

Well as long as ZS is up and RSK is on cooldown and TP buff has more than 5 seconds left on it, you can use FoF without much ill effect. Its still twice the damage as the average BoK which is what you would be using instead. However, its probably not as much damage as a Jab + 2x BoK.

EDIT:
Unless the intended tooltip isn't what is actually going on in game, I've basically found zen sphere basically useless to use in single target cases. (less overall damage than a no'kaled proc).
I think its still the same (not fixed), based on what the datamined spell data is showing. They didn't actually fix it in-game.

EDIT:

25k iterations stat weights with 13 /eps change (and 'fixed' zen sphere as the change intended):

Weights : Agi=3.4970(0.0799) Exp=3.0034(0.1260) Hit=3.5532(0.0806) Crit=2.1611(0.0794)
Haste=1.5173(0.0793) Mastery=0.4510(0.0789)

EDIT:
Broken zen sphere weights:
Weights : Agi=4.6517(0.0816) Exp=5.0837(0.2512) Hit=2.9728(0.0820) Crit=2.6174(0.0813) Haste=5.4197(0.0809) Mastery=0.7520(0.0808) Wdps=11.2929(0.2445)

I'm getting these ghetto weights with zen sphere... i'll figure it out.

Going to do some level 85 heroic non-druid profiles really quick and see what turns up. I'll include the 'unfixed zen sphere' and 'fixed zen sphere weights.

But for whoever asked about haste rating losing it value, the 13eps change was more than enough to butcher its value.

I had this problem for a few days while leveling and a day or 2 after hitting 90. The way I fixed it was to purchase dual spec, swap to mistweaver or brewmaster then switch back to wildwalker. The bug I had was preventing the aura from giving the extra chi and by doing so refreshed the aura.

At the moment, it is absolutely not worth using.

Values I'm using from my monk:

FoF 15,505 - 23,383 damage each second.
Jab - 4,651 - 7,015 damage
BoK - 24,808 - 37,414 damage + 20% dot
RsK - 44,614 - 67,345 damage

Over 4 seconds, I will do the following amount of damage:

FoF:
62,020 - 93,532 damage + 0.75 stack Tigereye Brew

Jab x2 + BoK x2
68,481 - 103,823 damage (assuming behind the target to get 20% dot) + melee swings + 1 stack Tigereye Brew

Jab x2 + BoK + RSK
83,725 - 126,271 damage + melee swings + 1 stack Tigereye Brew

I gave some more detailed feedback on the beta forums, but this ability is not worth using at the moment at all:

[Monk] - FoF detailed analysis. - Forums - World of Warcraft

With current levels of energy regen, damage per energy is less important than raw damage output since we aren't limited in energy or having to pool. This can change if/when regen gets nerfed, but at the moment there's nothing stopping us from consistently being able to spend those 4 gcd's without any hesitation.

If energy regen gets nerfed this will of course change. But I did edit my post to reflect that FoF gets us close to a stack of Tigereye Brew, which is something I did overlook at first.

There's no "if" it gets nerfed here. GC Has already stated that it is intended to be 8/sec energy, sadly. We might be able to talk him into a 9/sec or 10, but probably by next build it'll be back to 8.

So, at 9e/s (8 baseline plus energizing brew) we can jab once every 4.44 secs or, rather, we get 1/4.44=.225 jabs per second, plus .45chi per second. From tiger strikes we get another .05chi per second for a total of .5chi/s. With that chi, we get to cast this many actions per second:
-1/8=.125 RsK per second, costing 2/8=.25chi
-1/25=.04 FoF per second, costing 3/25=.12chi.
With the remaining chi (.5-.25-.12=.13) we can cast .13/2=.065 BOKs.
At 11% proc rate, combo breaker provides .225*.11*2=.0495 TP/BoK casts.
We also need to cast tigereye every 90s or so: 1/90=.011; and energizing brew every 60s: 1/60=.0167
So we get to cast a gran total of .225+.125+.04+.065+.0495+.011+.0167=.5322 actions per second. However, we spend 4 seconds casting FoF (3 secs more than your usual gcd), so we cover 3/25=12% of the time on it: we average .5322+.12=.6522 actions per second (or 39.14 actions per minute); and that is with 0haste and 0mastery.

Taking your average melee character, hardcapped at 40 actions per minute (1.5s gcd), I'd say monks are in a pretty balanced spot. Now, we could argue that casting more spells per second is better or worse designed, but we lack information on any fun/button-smashing ratio so I'm willing to call it good with a caveat: assassination rogues are the prime example of a heavily resource-restrained spec, much like WW at the moment, but the stregth of the spec lies in the fact that energy-pooling has some meaning even in sigle target; ww monks, on the other hand, don't get any rotation-tied advantage from doing so.

That kind of implies it. The point is: monks are at the same spot as every other mêlée (save for combat rogues), and that's fair; they simply have one more degree of freedom: energy pooling. I simply don't see any reason for a increase of the base regen.