Let me be clear. Pre/Post is entirely irrelevant, as they don’t create the policies and procedures that our Support staff follows or the systems that we use. Just as Vivendi had no involvement in our policies before them.
Let me cover a bit of what you have experienced though and try to clarify a bit.
Not exactly. Due to how the standard mechanics work in World of Warcraft (non-Classic), as far as I know, this item should have been available to be traded.
I’m not certain why your friend couldn’t trade the item to you. You may not have been on the loot list. The item comes from a mob in the dungeon and not a boss, so it’s possible you weren’t there and eligible. If there was a specific reason that our staff found they would tell you. If they couldn’t find one, then the only real option would be to submit a bug report. In either case, we are usually not able to assist.
To be clear, No, we wouldn’t have. Our staff is always happy to try to help fix mistakes, but there are policies around which errors we are able to help with. You purchased the Blood Drain enchantment from the Auction House, apparently meaning to get the Illusion. We wouldn’t be able to refund the purchase or provide the item back or the item you intended to receive.
Not necessarily, but content changes and is added over time.
Based on your ticket you expected the enchantment to be added to your transmog appearances. The appearance collection is something that is a fairly new addition, which you apparently knew about.
Even so, we try to include what information we can about the game through various sources. Some of those are found in Tooltips. We also have information that is provided through our various Support Articles (which can be searched through the in-game browser). There is one specifically on weapon enchantments.
There are also sources like your fellow players, the forums, or sites like wowhead.
I am sorry that you haven’t had a good experience, Mementomoori, but our inability to assist has nothing to do with Activision or some assumption that we don’t care.