I'm talking about why their minds got to this kind of stuff, not why they implemented the way they have. Prior to them talking about the Path of the Titans, a vocal amount of players wanted Blizz to introduce some sort of end game leveling system. IIRC, they put out that they were talking about some stuff internally, eventually announcing and discussing the Path of the Titans at Blizzcon. A end game leveling system where you would slowly unlock additional powers of your choice, that would expand with patches. Sounds awfully familiar.
They scrapped Path's for a variety of reasons, one being that glyphs already provided similar feeling power increases, and they felt it would need to too strong for it to be worth players time, something they didn't want to do. For Legion, they decided that a system like that is perfect for central power control, eventually realizing that it could work on an xpac-to-xpac basis. After showing it off at blizzcon and during early, most people compared it to the path of the titans. IIRC there were even a some blizz references.
- - - Updated - - -
Oh I agree 100%. Things weren't even this bad in 8.2, but now it's just too much. I used to have 3-5 alts that I would mess around with, but now, with all the extra steps needed, I really only bother with 1.