I'm hoping we'll get a Two Become One keyblade or Oathkeeper/Oblivion that give you a form change that lets you dual wield like Roxas. Some of my favorite keyblades from the series to return as aesthetic DLC. I don't want all of the DLC-blades to be Second Form.
Yes, and we've already seen several keyblades added as DLC. I don't think they'd add anything meaningful to the game that would take away from the main experience. Unless it's post game (but again i doubt they'd add entire worlds as DLC) then they would save anything additional like that for the Final Mix. There's a lot more that would go in to making World DLC than they would probably care to put forth at the cost of, say, 10 a world. Disney gets a cut if it's a disney world, hiring new voice actors for said worlds, even original worlds would have to hire new voice actors if the DLC includes characters that weren't in the main game, then there would be the work using the new engine to make these new areas. If they added something to already existing worlds, it wouldn't fall under the category you're implying. A lot of extra work they would be putting in for some DLC. They will probably be focusing much more on FF VII remake as opposed to DLC for KH3 to add more worlds. As soon as they secure part 1, MAYBE we'll see the Final Mix for 3 pop up. Unless they hire another group to work on FF VII, Nomura is supposed to be 100% involved with it right? Which development teams are supposed to be focused on VII and which ones were working on KH3? Because that's an important factor too when considering moving resources around to add extra content to a game.