Well... I think it's going to be OK. WoW Classic was created back in the afternoon where Blizzard was still good company. New Blizz did not need to hear about creating wow classic gold, even after people have been requesting it long time and responded by things like:"you feel you want it, however, you don't!" Once they saw participant numbers falling in wow, and relise the popularity of private servers (who operate patch 1.12 most of the period ), only then have they considered this may be a good way to find a little extra subscribtion cash with very litle function as WoW Classic already exists.
And I think Blizz would seem silly when they changed the WoW Classic match. Because, why launch WoW Classic if it is no longer the exact same game, and second, shifting WoW Classic would require more work and resources, thus increasing price. And of course changes would be insecure as players do not want them (and they know it). Think about it this way - the less they work on it, the better WoW Classic will be recieved - now what firm would pass on that? Imo we'll see substantial group replacements, exploits, raids being cleared quite fast, etc.. Ofc we'll receive all the good things with Vanilla, but we'll also receive all the bad things back, and Blizz won't alter some of it.
You want feeling? They want profit - and they're losing it by losing a good part of hc players. I will be surprised if they branch wow following releasing WoW Classic - retail for casuals and whole new dev for hc players. Retail with WoW Classic doctrine - nah its too late for this, I think there are individuals who enjoy present content more than we think, and they dont want to lose their money.The only issue regarding category changes is I am not sure how are they going to handle pvp and pve balance of each class if they start doing this, and would they bother, atleast at the beginning of WoW Classic, a great deal of things will be determined by how a lot of people will play it if they see extra gain , they will develop WoW Classic farther in the WoW Classic way, but not retail.
This alone gives you joy and fun in WoW Classic. Folks are not only going to play rogue/warry/mage/wl because the loot is not personal. You want to have hunters to pick up the mail items. A whole mage/wl raid will be weaker because you lose out on all of the class items or mail items that will fall. Classes have particular functions like shaman only heal, tank only warry. But this was exactly the same in WoW Classic and gold in wow classic was nice for most of the people. I think it's going to be another way around. Retail obtained mythic+ and new endgame content in which you race into world firsts. WoW Classic is going to be a lot of people who want to relive their experience from when they're young, take it slow and revel in.