i presume it does sorta. i lvled my dwarf warrior from 115-120 last weekend, it was lvl 7 neck at the start. i leveled via islands, and then geared up to ilvl 400 within 12 hours played of hitting 120, but i also hit neck 50, so there is some catchup i think, at least to bring you to 50 and essences.
but as mentioned, an account bound HoA AND essences would be so good for alts. im sure there are ways around us being able to farm tons of ap on each alt. maybe making the cap 1 level a week as someone mentioned. im sure it could easily be done, but that would mean one of the core aspects of blizzards plans for this expansion would be gone, ie. us farming ap till our brains bleed.