I think Rishab is a moderately good looking guy actually. If he gets the right haircut and right hairstyle with a little grooming, I think he can look great. He has a very expressive face and can emote certain emotions through his facial features. Also, he does have nice eyes which I've noticed throughout the show. I think that he has curly hair which most men don't have.. Usually men tend to have straight and thick hair especially in south Asian counties. Since curly hair is less common, it needs a special way to tame and groom it which I feel the production house or Rishab really fail to do.
Rishab is a very flamboyant guy with a nice attitude so I don't think we should really judge his looks so much. His acting isn't the best but lately I've seen him grow as an actor especially his intense scenes with Asad. I don't think we should compare him with Karan or the other heroes since the main leads are kept for primary desirability ... Rishab is more of a parallel lead/love angle.
But yes, he needs to take care of that hair of his and also maybe sport a small stubble, not too much because clean shaven doesn't look the best on him neither does a full grown stubble/beard...