I do understand that thing cannot be implemented in one go, like many other features they can implement it xpack after xpack no need to go back and retroactively change thing; if they didn't come up with the garrison thing but implemented a true housing system not tied to a single xpack at this time after 3 xpack we would have a solid and refined system with ton of shit to farm for.
Same goes for mount and pets i won't ask for them to go back and make the baron riverdare horse or ashes of alar able to wear armor but they can always implement new one with that ability the same way i won't ask to make brokentooth able to wear armor still new pets can; also why it's not possible for dk and warlock to customize their summon beside the model blizzard decide with the glyph? That not even require much of work on their parts.