Keep in mind that half the people given Keyblades got them in ways that don't make sense or....just there.I mean Riku's comment could be reduced to his lack of knowledge of the keyblade (although reality is that Nomura didn't expect a sequel and/or didn't think about whether there should be only one keyblade master). However, I do think that he was thinking of other keyblade wielders possibly existing as Triton obviously knew about others that were not Sora and Leon knew about the keyblade, so there had to have been other wielders besides Sora. On top of all of that, Mickey has a keyblade at the end of KH1.
I think the only people I'm mad at having a keyblade out of the current lineup is Axel. He was just SO much better with the chakram and I personally find his keyblade ugly and uninspired.
The new keyblade masters that are the villains (Foretellers), I'm hoping a significant number of them are wiped out in the side-game before KHIV (kinda like CoM cleansing Organization XIII before KH2). That will allow a reduction in keyblade wielders and Nomura just needs to stop with giving everyone a keyblade. I mean, it really makes me question why Axel got one, but Donald and Goofy didn't. NOT THAT I WANT THEM TO, but the in-game logic is off. Axel got one by being heroic? So what do Donald and Goofy do?
Has Riku always had the keyblade? Like....how did the Soul Eater transform into the Way of the Dawn? Has it always been a Keyblade? Secondly..............K A I R I. She....touches Aqua's Keyblade by accident and her light JUST allows her to weild one? Keep in mind that her Keyblade was HAND-BASKETED BY RIKU OUT OF NOWHERE. Just like Lea, I still don't understand how these two got a Keyblade. The process seems so....underdeveloped. It just makes no sense anymore.