He hasn't really had much time to do anything in domestic cricket.
Scores of 62 and 63 against the world champions by a keeper sounds pretty damn good to me. The 63 against Pakistan was during a very important match, he was also opening! WOW! that's some great scores against the all mighty ZIMBABWEANS
I wouldn't take those figures too seriously.
There's no doubt that he is a promising young player, but does he have the mental toughness of Patel? Patel seems to already have everthing Karthick can offer + some international experience.
Free pass? You obviously have no knowledge of selection policies and quite frankly the Indian selectors must see more in Patel than in Karthick. His name has mainly become popular because of the hype from non-Patel supporters.