OOO, don't.
Don't you remember the negative reaction from the community with the 1st gen Regalia?
Please, don't do that again. With anything.
We do need variety but NOT promo items. Some people kept some just to resell later, it's a business, that you're affecting, in a negative way. So, please, don't.
It's really not something the community wants or likes, so please don't do it. :< (I am not stating that I know the absolute will of the community, it is simply something I've noticed on the forums and in-game that may not apply to everybody)
We do like variety but not with promo items...
Give a +1 if you agree, to show OOO that they shouldn't be doing this.
Edit: Here I've answered a few arguments you might bring up: http://forums.spiralknights.com/en/node/61776#comment-458155
Bringing back old promos is practically the one thing I don't like about how OOO runs Spiral Knights. You should have seen me when I found out that two more of the main things on my signature set, what I call my Fire Suit(which secretly but not a secret as of now is based off a Charizard) were available in the last promo.