As alluded to in my previous post, I'm very much on @Dreiko Shadrack's side here.
I disagree with @Aura Knight; the relevance of an item doesn't really matter here. Over the past 12 months, there has been a consistent argument made that, if people invest real money into an item, then care should be taken when changes are made to it, regardless of whether the item was made ten minutes or ten years ago. In some cases, an older item has been considered even more important precisely because players had time to get used to it.
The only reason this is even a matter of debate is because Tribal Shaman wasn't a particularly good item before the change. If this were a Doomlight armour that had suddenly been modified into a version of Bard of War, people would (quite rightly) be extremely upset. Changing the central theme and target audience of an armour represents a direct, unavoidable challenge to the argument that care should be taken with changes made to a premium item. Even if the item was originally bad, and even if the item it becomes is good (both of which apply to this armour). There is no reason this couldn't have been made into a good armour with quickcast player related buffs, which would have still reached the original target audience.
Beastmage may be popular, but there was no reason or justification for turning this into a beastmage armour.