IMO - Both Nimrit and Ankit had/have potential.
Ankit had it especially when he fought and moved away from Priyanka, and Salman gave him that hint too on WKW.
By the time it was Ankit’s elimination week though, his game for the few weeks prior was reduced to that of being Priyanka’s popat, just involving himself in her silly fights. So I had no problem with his eviction, Salman also stopped giving him wake up calls and was giving calls to other HMs to nominate him based on what his game had become.
As you said both Ankit and Nimrit had/Have potential.
But point is if sumbul finds nimrit has potential then why she did not find potential in ankit too. Answer is simple because sumbul is blind follower of mandli. If Ankit is priyanka's popat, who is nimrit? What is her individuality or where is her individual game.
And Ankit got taunts till last day from BB. He got most taunts by BB followed by Sumbul and Shalin.
When Sumbul said that nimrit and shiv are better than others in her pov, she was right there as it's her point. But the reasoning she gave for nimrit, that was a bit illogical. But point is, iss season main contestants dhaang ki reasons detey hi kahan hain. Why to blame one of them. Sab ky sab hi aisy hain.