I would Raees should get a sequel. Not because the movie deserves it but the presentation of SRK's character deserves. That is a character and a look that deserves to be in a better, more entertaining movie.
Since he had a son, you can just make it his son's journey. Take away the rest of the cast, maybe include Nawazuddin for a bit where Raees Jr. kills him as an act of revenge. Otherwise make it a journey for him from being a man who's been told his entire life to keep his head down and be a civilised person and finally embrace his true instincts and become a gangster.
I would like to see the world of Sultan again but that's a finished story brining it back would be pointless. Kick as most would say is a good idea.
Aamir should be in a PK sequel dealing with the consequences of bringing his species to earth. It can be classic RKH story of learning to accept others and becoming a closer community.
Saif Ali Khan should be in Race 4.