Not just alternate timelines, either.
Way back in October of last year, we did a brief series on potential playable races in whatever the upcoming expansion happened to be.
Let's be up front.
In patch 7.3.5, Broken Shore-style level scaling will be implemented for all previous content, with the old-world Azeroth all scaling to a max of level 60, Outland and Northrend scaling to a max of 80, and Cataclysm content scaling with Pandaria up to level 90.
Garrosh Hellscream is headed to the Nexus -- perhaps an appropriate epilogue for a story that swept through five expansions before its explosive finale.