Well, with the emphasis on doing dungeons, raids, and PvP in this expansion, if Blizzard decide to scale all old world zones as well with the next or in a patch, then that will be the final push for me to stop playing WoW. I've played since Vanilla, and gone through the good and bad, but this would be the last straw for me. It would just make the game not fun for me. I already loathe having to go into Suramar City and that all the content at level 110 requires you to do it.
My impression is that Blizzard has suddenly stopped listening to the more casual players and is trying to suck up to the more "hard core" players who bitch and whine constantly that things are "too easy".
I wouldn't say that Suramar is for the hard core players. You aren't forced to rush through it, and it really doesn't take a lot of skill to finish it. For parts of the city that may need more than one, there is always LFG. Honestly, there really isn't anything wrong with Suramar being a central part of this xpac. Makes perfect sense story-wise.
But anyway, Blizz isn't going to be scaling all old world zones this xpac. They might the next one, but the only thing they said for certain is that they would like to eventually do it. I think a lot of people are jumping the gun and making assumptions on how the system will work when it hasn't even been implemented, let alone discussed in-depth by Blizz.