Do you think Red will appear more after Black/White Arc?

if they make a gray arc then i think they might include him a bit more. since in emerald arc they all came

Black/White Arc: No. Why?

Because The Black and White arc will mostly just revolve around Black, White, Cheren, and Bianca. This is what has happened for the longest time when ever they make the first games of a new region. When they make a Pokemon Grey Version (IF they do of course) then in the final battle of that they will bring in all of the characters (just like they did for the Yellow and Emerald arc)

Yes