It feels like Blizzard has created a new level 60 progression that is here to stay as a replacement to increasing levels when releasing a new expansion.
I think it would make a lot more sense for Renown to be used in 10.0 as opposed to increasing the level cap to 70 AND adding on top of that some kind of a new progression system for max level players. Since leveling itself won't take more than 7 hours, why even bother adding it for expansions after SL.
I think Renown would a be good base progression system for max level on top of which other new systems can be based and tied to, similar to the build-your-own talent tree conduit system. Very "next-gen" like innovative systems IMO. Really hope these two systems can stay in some shape or form beyond SL and for leveling to never increase beyond 60 ever again.
Now if they could just redo the leveling experience of previous expansions to include max level zone stories and end game bosses in a condensed, solo friendly version, similar to the new starting experience, that would be awesome!
And While at it, might as well create a solo queue for old expansion raids for all but mythic difficulty so players don't have to travel to the entrance, it would make farming them for xmog, mounts and pet collection much more convenient, a much needed QOL feature imo.
For new players who just started playing at the release of 10.0, they can be offered the choice to level up from 1 to 60 in 10.0 so both old and new players can play together. Or, if this is too difficult or undesired, they can level in 9.0 from 1 to 60.
In Lakrin's words in his comment below, he seems to fully understand what I am getting at: " the argument is more that leveling hasn't really meant a whole lot the past few expansions other than numbers get bigger. " THAT plus the fact that they changed it so it doesn't take more than a single evening to level up to max in SL.