The answer to this question:
Maybe? I'd like to see actual reviews when it hits on June 2nd. Should be interesting if it does have better temperatures than Haswell (original) when over-volted. I don't think temps were the main issue with Haswell OC'ing though. It had more to do with extreme variance in terms of voltages to overclocked clockspeeds. Temps weren't the big issue though. They really weren't. You can just use an AIO and take care of that fairly easily. The bigger problem was the variance with 4770k - I mean, with IVY you could, generally speaking, hit 4.6ghz rather RELIABLY if you used 1.275V or 1.3V with proper cooling. Same with SB. Using 1.5V would get you realiable OC'ed clockspeeds (within 200-300mhz, usually).
Yes, there are exceptions, but Haswell was less reliable in this respect. You can use 1.275V on Haswell and get anywhere from 4.3ghz to 4.7ghz depending. That really wasn't the case with SB or IVY, even though ivy had higher OC'ed temps.
Now silicon lottery still applies of course, but SB and IVY seemed to hit certain clockspeeds much more reliably at set voltage levels. Granted, with Ivy, you *needed* outstanding cooling moreso than with SB. But if you used 1.3V, you could generally get 4.6-4.8ghz. With Haswell it truly was a crapshoot.
Not sure if that situation is fixed, but I sure hope so. I don't care about the temperature.s That can be fixed pretty easily within reason. But the voltage > clockspeed variance; if that's better on DC then I could see myself getting one.