We all have played as Roxas in the beginning of KH2 and I personally enjoyed it. His ending is even sadder than BBS.

Knowing that he has to return to Sora in order to save him. He hesitated at first, but if you were in his shoes, you would feel the same way. "I am me and no one could ever be me" "My heart belongs to me". In DDD, Sora finally told Roxas the same thing and I got "the feels". Roxas deserves to be reincarnated with a body of his own because I'm counting on a Axel/Xion/Roxas reunion.

 

I am also a huge Naruto fan, and my fantasy is that Sora can go to his conscience and voluntarily talk to Roxas whenever he wants. Just like Naruto and Kurama. Roxas can lend Sora his power to dual wield the Oblivion and Oathkeeper keyblades. With the power of two hearts, Sora will be the trump card the Guardians needed to vanquish the Seekers.

 

This is all my imagination, but do you guys prefer Roxas to be playable in KH future games? Maybe a spin-off?

but he deserves to have his own game and not be about organization 13.

And what kind of "own game" do you think he should deserve? The most important story lines of Roxas were told at the beginning of KHII and most of 358/2 Days, and everything left was either not important because he was inside Sora or came in a cutscene like Re:Coded and 3D. Roxas took enough roles especially as "Own title" and I think having him playable on KHIII with his own body would be more than enough because it is the time for giving more space to others.

Roxas shouldn't have too important a role, I don't think he should be one of the seven light's, nor do I think he should be one of the thirteen darkness's either (Even though Young Xehanort confirmed he isn't). He will however participate in the Keyblade War as he is a Keyblade wielder, I'd love to see him, Lea and Xion go against Xemnas or even just Roxas Vs Xemnas, one on one since he never got to in 358/2 Days.

I've replayed the beginning to KH2 so many times that I agree with you. I enjoyed Roxas prologue so much :,(