The binning of Hawaii actually leverages learning from our CPU side by doing what I call "power binning". This means that speed, static power and dynamic power are all taken into account in the binning process. The onus is to, as much as possible, keep the same power utilisation profile from one ASIC to the next (at the same clocks) meaning that one ASIC will actually be operating at different voltage from another while performing very similarly from both a clock speed and power perspective.
ASIC "quality" is a misnomer propobated by GPU-z reading a register and not really knowing what it results in. It is even more meaningless with the binning mechanism of Hawaii.
The control of the fan is intrinsically tied to the PowerTune implementation.
Its a new high end ASIC, with a different engine configuration (much more fillrate) with some new architectural features, so for sure there is plenty to play with and tune from here. Tahiti was a significantly different architecture from the previous generation, though, so the room for optimisation was likely greater on the whole.
As explained before, the ASIC temp is targeted from a performance perspective. The fan control mechanism we (and you) can target any temp you want, but from a performance/acoustics perspective higher ASIC temps are going to offer greater benefits if the overall solution is thermally TDP limited in any way.