I've never supported the idea of exclusivity in any context, and this is no different. I paid because I liked warframe and wanted to be a little part of it. I was, and that's that. I got what I paid for and I don't see any reason not to put them out there again. If I could add maybe one caveat, I prefer to see the items added to the game and obtained via events or story quests. I think that would give them some emotional significance, which if done right could also play on the founders experience.