I honestly don't think 70% will buy - well 70% of people who have JUST purchased SampleTank2 for next to nothing MIGHT, but long term users (I purchased my full version of sample tank in 2004 I think, perhaps even a little earlier??) will most certainly think very long and hard about an upgrade, as most of us have been forced to move to better products - I now have Mach 5 and Kontakt.
I have to add, that because of the way they have undertaken this essential updating of one of their main products, I have become very worried indeed about their whole philosophy with regard to timely product development, so I have not upgraded any of my other IK products for some time now.
My Tracks is old and no longer works, so it is not installed.
Amplitude does still wok and I use it occasionally.
Ampeg also just about works though it's lumpy. Once it stops it goodbye I think, as I have been caught too many times by software companies - I'll just mention NI Kore, TC Powercore and Gigasampler - I am very worried that this complete lack of focus on their Major product line might mean these PC based products might go the same way!
I have also managed to get Sampletank stable enough to use by having it installed on a 32bit machine and linking to my main machine via Vienna Pro.
So if IK ever do release the 64bit Mk 3 version, for me to ever contemplate spending any money, it would have to be way better than Mach 5 or Kontakt (and from the Namm video it doesn't look like it offers anything better) or be EXTREMELY CHEAP - and I used the word cheap deliberately and I mean cheap not reasonable!!
Nigel