Who would you have picked to replace Sehwag? I don't see many evident choices, besides Karthik - he probably was the best bet from IPL performances. Kohli wasn't brilliant, Uthappa was shabby, Badri is not T20, Vijay never got enough opportunities...am I missing out on any other major fringe players?
Pandey?
That's the thing with you're Raina's and Sharma's. They haven't played enough cricket and still haven't developed all the skills they need to play international cricket. They might look good in the IPL, but international cricket is a lot tougher.