I guess people have said that, during this pre-release period, prices have gone up, because more MT has been generated so people can afford more.
Last year, at least on PC, lots of MT sellers were apparently farming MT somehow, or buying in mass amounts and reselling, and MT became cheaper than VC. Many people used a lot of MT to buy packs but a lot just bought specific players straight off the AH.
I think more of the latter and/or pack odds were astronomically low, so there was insane MT inflation and Current Amethysts were selling for over 1 Million MT at one point. Or, in terms of USD $ value, approximately, say, $20.
When most people are spending real $ on VC and not MT, then that should lead to better supply because people can only rip packs with VC.
There have been some changes this year that might frustrate/slow down MT selling, but it remains to be seen if it can still operate at a similar scale as before.
TL;DR: Have no idea.