So What about Monks and Epic post U9?

[Ssmooth]

If it's gonna require your to go full-****** on Wisdom to get a DC that'll actually land then yes, dump it and don't bother. What's the point if you won't be able to hit or damage your target?

However . . . how well are the 40 DC stunning fists working on Lamania? Are they complete garbage or good enough?

With the increase of epic mob saves, a 40 stunn DC will probably work less than 50% of the time on regular mobs, almost never on ogres/WF/trolls. That is if your a dark monk. The will-based stun of the light monk will probably continue to be effective, or at least more effective than a traditional stun.