Quote from Bagstone
1) You can upgrade one affix at a time, and most endgame items have 6 affixes. So essentially it's rather pointless. You might as well say "keep all your crap items with 6 affixes, you can upgrade them". From what we have seen, almost all stats are being buffed and can roll much higher values, just think about the 3k weapons.
2) He said that even people with awesome BiS gear should find upgrades on a regular basis, that pretty much confirms that all 60 gear will become useless at some point.
3) You're right that you shouldn't sell gear just yet. The expansion might still be a good year away. Why would anysone sell their gear now? That'd be stupid. On the other hand, I'll take it, so go ahead.
4) The interview has been posted before, even on the front page...
I understand the video was posted before but many people seem to have missed the comment on level 60 items using mystic to gain level 70 stats. THis is why i posted it.
Certain players with items with perfect trifecta might be interested in just Enchanting the main stat on gear. I thought it was good info to share tbh.