In sports, there are other features which are equally important such as hard work and temperament.
I don't know how you can say Virat is less talented? I mean he was performing superbly from his under-19s and in ODIs has been supremely consistent right from the start. He has a good range of strokes both on-side and off-side, has decent stance and balance (without any exaggerated back and across movements) and a good technique to boot, so I guess this is what talent is all about. Add to these qualities he is a natural athlete, and a superb fielder.
We get the impression that Rohit is supremely talented mostly because he seems to have that bit of extra time when facing express bowlers. Usually he seems to caress with lazy elegance, especially when leaning into drives, or just taking a slight swivel onto the backfoot and pulling, all these give the impression that he is highly gifted than others. No doubt he is a talented player, but I always feel that he is not enjoying his stay at the crease, always has a sad kind of look while he is on the field. He is getting out too many times via tame and soft dismissals. He still needs to put in lots of hard work to succeed consistently. Already, he has been given more than his share of chances and it's high time he delivers consistently.
Regarding Umar, whatever I have seen of him, makes me think he wants to play too many shots too early and again which is a result of lack of temperament. As many players have always said, talent will only get you chances but it is temperament that will make you great.