As far as 188 rear hub play goes, if it's a 2013 wheel, with the black left end cap, that's (finally) been 100% addressed. the axle/bearing tolerance is much more snug, there isn't the radial space that was previously causing the lateral play.
Incidentally, on older 188 hubs, I was putting a thin coat of fingernail polish(!) on the bearing seat areas to tighten up the fit. It works. Sucks that you had to do that, I know.
I prefer the 188 hubs over the DT 240s. Better geometry, night-and-day coasting drag, etc. And I've ridden my 101s in the rain (a lot, they're on my commuter bike) and they're 100%. I do occasionally open them for inspection, but haven't ever seen moisture past the seals. A couple customers have toasted one bearing here n there, they've been the abusing types in general, and replacement is easy.
Interesting. Wonder if Zipp will take a wheel back and replace the hub with a 2013. The 2012 FC still has the play. I checked a fellow competitors 303 FC clincher, same issue...assume his was a 2012 also. The wiggle/play, even when you go slightly tighter on the pre-load, is still there.
Or, I guess I could just send it to someone like Fairwheel or Wheelbuilder, and have them put a new Alchemy UL hub on the back and string it back up. Problem solved.