Reforging should also allow you to swap the stats of similar items. This would add a more unique feel to the game as people would customize there own gear sets instead of everyone looking the same. Example: You could be wearing your old pvp sets from s1 and s2 but they would have the stats from s8.
That exact thing has been suggested many times before, and many flawless reasons for doing it have been given, but Blizzard, if I recall correctly, does not care. They have some stubborn, archaic notion that being able to tell how strong someone's gear is at a glance trumps both character customization and retaining use for old models.
(Keep in mind that many people had also suggested a compromise in which only class-specific tier gear could be swapped, so you could still tell someone's class at a glance, and they still refused)