Legion was a great expansion for anybody who wasn't trying to be optimize their character like they had done since Vanilla-WoD.
Anybody who was looking for BiS lists, or at least trying to stay relatively competitive with other players was in for a nightmare of a time.
Two shit legendary items on your first character? Might as well reroll, cuz you aren't getting a third until the Karazhan patch.
Class balance and design on release was pretty awful, then it got better, then it got worse (IMO).
Legion was absolutely the beginning of the end of my enjoyment of retail WoW entirely for me. Chores to stay relevant, random loot drops... I really did not have a good time. Not to mention a lot of the point of borrowed power in the first place was to introduce new mechanics and ideas that may or may not be everybody's cup of tea, but they would be LIMITED and not show up constantly or even ever again potentially...
...except then they did show up constantly and became part of a lot of classes' base identity. Chains of Ice Cold Heart buff, Obliterate having a random chance to refund runes, consuming Hot Streak has a chance to make your next non-instant Pyroblast deal more damage... Unholy is finally getting away from all the, "Death Coil reduces the CD on these cooldown abilities" that made the spec rather annoying to play, but they still are plagued with all the borrowed power, "this cooldown empowers this other cooldown and makes it stronger, so figure out the correct order on all these
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