If you look closely at Sora KH3 costume, it shares similarities to Roxas. What does this mean?

Probably nothing, but super cool find, and great attention to detail.

Man you've got eagle eye type vision. Anyway I'm pretty sure there's no deep meaning behind it other than nomura likes to reuse some of his designs that he really likes. It would be awesome if there is some connection between his new outfit and roxas/ventus though

Sora is Jason Todd confirmed. 

That's just nitpicking man. I know HMK did a video on this but I think is to far fetched. It be nice for there to be a connection and contribute more to the story! However I wouldn't look to much into it .

Nice to see all the effort, but I do too think it is far fetched.

it's probably just Nomura pulling from old designs for inspiration

It's an awful big coincidence, that's all I'll say. 

Nothing. It just is his clothes for KH3. He has to be stronger you know in order to be one of the thirteen.

I for once think that it isn't just a coincidence. I believe that it's the influence of Roxas changing Sora due to his unique status as a nobody that borrows elements from more than one person.