This ability is an awesome aoe nuke and when patch 1.0.7 drops it is going to be amazing.
The problem here is that it is an aoe ability with a knockback. The ability is completely counter productive with intention of using it more than once. This is especially annoying when using the blinding light rune. When I stun a pack of mobs it is usually to control mobs not to lose control of them.
The only way to really retain control of this ability is to combine with with cyclone strike basically using an extra chunk of spirit on top of an already fairly costly ability.
All I ask is to remove this annoyance from wave of light... Leave the knockbacks to lashing tail kick.
So, I have been running with a 0spirit gen WoL build for the last 2 weeks in prep for 1.0.7 when this will become my dominant build.
I have been doing a LOT of thinking about it and here is my conclusion:
I think that, initially, Blizz wanted Monks to be a "damage avoidance" class in every single respect.
To achieve that archetype, they gave us tons of dodge, then dodge skills THEN they also piled on TONS of soft-crowd-control built into all of our skills. The third hit of FoT knocks back (which REALLY sucks for non Thunderclap users) the third(?) hit of DR "dazes" or "stutters" the mobs, the second hit of WotHF stuns and the third hit knocks back.
Then they attached these "soft-CC" mitigation effects to nearly every one of our skills.
LTK - knockback (even the major DPS oriented runes that you would WANT to spam have this!)
TR - knockback (making it nearly impossible to use like baba WW)
WoL - knockback
DS - root (the only hard-CC yay)
Cyclone Strike - pull
SSS - invuln
What ended up happening is that Monks, on average, WOULD take far far far less total hits than other classes even when in melee range.
This was actually pretty cool in 1.0.2 when mobs hit like trucks and LTK:Sweeping Armada was on a LOT of top monk's skill-bar.
Then in 1.0.3 they nerfed Inferno DPS so hard that 100% of every class switched to a 100% offensive build orientation.
This made "soft-CC" VERY undesirable because incoming damage was no longer as much of an issue as outgoing damage.
They eventually added Monster Power but this increases the requirement for mitigation at a FAR lower rate than the requirement for outgoing damage. (mob DPS increases much more slowly than mob HP)
And so, we are where we are. All of the skills you WANT to use have soft-cc attached to them from back when Monks were meant to avoid taking hits.
My proposed solution:
A. Stick with it, make it more of a class-core mechanic and make a TON more movement-altering skills to go alongside the soft-cc knock backs and stutters. (FoT:TC being the only REALLY reliable movement skill that doesn't take MORE of the resource the soft-cc skills themselves use)
B. Give up on monks "avoiding" damage and accept the fact that this is a Diablo game where people WANT to wade knee deep in the bodies of their slain foes. Change most of the soft-CC to conditional damage or conditional hard-CC (stuns/roots) or just remove them completely.
As the OP states, WoL would be a FLAT OUT better skill without the soft-cc.
When removing a "beneficial" mechanic would make a skill MORE desirable ... you know something needs to be changed.
-Druin, the happy monk