I actually think Solo is an awesome reflection of the original Star Wars, with a bit of reverse Hero's Journey. Having a deeper villain is in line with the through line in ANH and ESB.
Maul being the "deeper" villain could work with Star Wars: Rebels. Giving a reason why Maul was stranded on the planet he was found by Ezra....cause Han (or Lando for that matter) left him there, or disabled his ship's hyperdrive so it was a one way trip.