Obviously he should make it as it was a commercial movie and till 2017 it's adjusted nett was around 165 crore means as of now around 180 crore.
Though it was average movie but got negative response only and only due to the VERY HIGH expectations it created among audience.
So I still feel there should be a sequel to Ra.One and make it larger but should also take some visionary director rather than handling big projects to newbies like Anubhav, ALR etc.
Climax for Ra.One was below average as it was in slow motion and for children's with fun here and there. Should have made in a hardcore way then WOM could have been little different.
Nevertheless they SHOULD TRY IT.