It was considered, and while I think we tend to agree it could be a lot of fun, because of how wild some of our class changes have been and will continue to be throughout Season of Discovery, Arena not something we plan to pursue. Put simply, no phase of Season of Discovery will have the level of balance we’d need for arena to be successful. Original WoW PvP works because its generally larger group PvP that you engage in (other than ganking or getting ganked, which is rarely fair). Arena and small-scale, highly competitive organized PvP really wants a level of balance that we likely wouldn’t be able to deliver in the ever-shifting, dramatically changing meta that Season of Discovery will be. Chasing the level of balance we’d need for it to work is not likely a good use of our development time. We’d rather put that into future phases’ abilities, new PvP events, new raids, new items, and other new content that will be exciting for the largest amount of players.
Sorry to burst a bubble, truly. I just feel its helpful to set expectations about what Season of Discovery is in terms of PvP and what it is not.