What I think isn't very interesting, but this 85mm is going to compete with the Zeiss Batis 85mm which, although two thirds of a stop slower, something that for most photographers using cameras with IBIS and that are capable of clean shots up to several thousand ISO isn't a relevant difference, is 42% lighter and 33% cheaper. Zeiss does tend to make rather good lenses, and to me, that choice, as an amateur or professional photographer, would be so easy that I wouldn't even pick up the brochure for the Sony.
You can always say that this doesn't affect those who want this lens and eventually will buy it. But it does. If not enough people buy it, it won't be profitable for Sony, and if Sony doesn't make money out of this, the progress will slow down, like it did with the A-mount cameras. Ultimately, that would mean less competition for Canon and Nikon who will be able to postpone the launch of their own, inevitable full frame mirrorless alternatives, leaving Sony with less competition in that area.
Leaving Sony alone in this market niche might be a strike of genius by Canon and Nikon. It does give Sony a more or less monopoly, but that monopoly has little value if the niche doesn't increase in size. At the moment, it doesn't. CIPA figures from December 2015 show that total mirrorless sales are 35% of the DSLR numbers, and still, the mirrorless market is shared among 4-5 players while the DSLR market is mostly shared by only 2. These lenses, which I'm sure is of very good quality, will do nothing to change that. The bulk of mirrorless buyers prefer smaller cameras with smaller lenses and mostly won't even know that gear like this exist for their cameras. Canon and Nikon on the other hand have the huge advantage of having their pro gear on exhibition at every major sports event worldwide.
By staying out of full frame mirrorless, they leave Sony fighting this uphill battle alone, and every mistake they do will cost them. Honestly, I believe launching these bulky, heavy lenses is a mistake. They should look to Leica, and develop some compact, state-of-the-art f/2 primes that would make professionals go "oh" and "ah". The dpr crowd will be less than impressed of course, but most of them won't be buying these big hunks anyway, so there's really nothing to lose.