Hideki Kamiya, the director of the original Okami and current head of PlatinumGames, has said that he wants to make an Okami sequel "someday".
When Okami originally launched back in 2006 - oh god, it's been that long - it was met with great critical reception, but didn't sell very well. In the years since, it's been re-released as an HD remaster throughout several console generations and has slowly built up a reputation as a beloved Capcom cult classic.
Although Kamiya is now over at PlatinumGames, a recent interview with YouTube channel Cutscenes has revealed that he's still interested in working on a sequel. In the interview, he says, "When I was making Okami, I would have never thought that I would leave Capcom and work somewhere else. Okami had been built on various ideas, and I figured that regarding things that didn't make it in, since I would probably have a chance to work on it again, I could foreshadow and expand on some things, addressing them in a sequel and answering player's questions while hinting at how the story ends."
He continued, "In Okami, for both the story and Celestial Brush's mechanics, we talking about how we could take time and developer these further in a sequel, making it more fun and stress-free. We obviously wanted to make a sequel."
Kamiya finished the segment on Okami by saying, "I started seeing people ask about these plot points that we left hanging, asking for a sequel. The more I see those, the more I feel this is work that I've left unfinished. There's always this part of me that thinks that I need to take care of this at some point. I want to do it someday."
Okami technically had a sequel on the 3DS called Okamiden, but it takes place further in the future, doesn't have Kamiya involved, and was considered as more of a spiritual successor than a true sequel to the original. A sequel to Okami has been mentioned by many of its original developers over the years, so there's certainly an interest in finishing the story.