I'll get my challenge appearance from the mage tower! I will! ... next expansion lol
I think he meant their might be a raid after the argus raid. Tier 21 is argus and tier 20 is tomb.
Next Xpac they will remove artifacts for sure, the thing is, building one entire expansion with a painful grinding for APs, nothing else to do on wow except farming APs all day every day so they can remove it all in 8.0.0... Seems that the only permanent thing gear-wise is the 15 slots, they are there since vanilla never got lower than 15, only higher (16 with bow off-hands, throwns and wands) now on legion they made a huge game-changing effect with the artifacts just to throw it all out 1year later. I bet the first quest on 111 will give you a 1010 weapon that you will easily trade for your artifact to earn 54 more stats dinging 150 main stat, yes they will reduce those retarded child-style 9digit numbers to a regular value again, its just like that so the kids can feel powerful with their shiny toys.