I don't mind it being a gem so long as the gem is re-socketable, otherwise that's just pathetically poor game design right there.
For me, the legendary items were never about the item itself, it was about the process you went through to get it. Back in the day, Thunderfury and Sulfuras were epic themselves but their process was never epic. The Warglaives of Azzinoth was nothing but a mere drop off a boss. It was an insanely rare drop but a drop none-the-less. There was nothing truly "legendary" about obtaining it because if you did the raid enough times your group was bound to find one eventually.
These legendaries were based off luck, not skill, and so the items themselves were more legendary than the actual process to get them.
Wrath of the Lich King changed this. The legendary items were difficult and time-consuming to achieve. You would be hard-pressed to ever obtain one purely by doing pick-up groups and you had to go through some challenges before the item was given to you. There was not as much luck involved like the old ones, it was all about how much patience you had and if you could donate the time to actually obtain the item.
Having a weapon is pretty awesome but legendary gems have the potential to be useful even past the tier they were obtained on. Dragonwrath was great but has been superseded by Dragon Soul weapons. This was inevitable, we knew it was going to happen. If it didn't happen in T13 it would've happened in Mists of Pandaria, just like every other legendary. But why take the time and effort to design a legendary that players will only ever use for a few months before replacing?