Being Alt friendly, now, at the end of the expansion isn't quite the same as being alt friendly in a more general sense. During the entire first half of Legion the game was downright hostile to alts. And in a lot of ways it still is.
Legendaries are the biggest culprit, but things like the Order Hall missions, Crucible and Titanforging slot machine mechanics are contributors. And honestly, until the catchup mechanics like Artifact Research and Unsullied Gear become available and useful, alts are going to be a serious time investment to operate.
If BfA starts out anything like Legion, it won't even be worth considering an alt until 9-12 months in. That's not being alt-friendly at all.