Dinesh Karthik is a talented and a very fine cricketer. He's athletic, technically solid, and a very good allround cricketer.
He's one of the most versatile cricketers in the team, willing to fit into the opening slot, middle order, and lower order and having bits of success in each area. His wicketkeeping is very good, I still say he's a better pure keeper than Dhoni is, and his fielding is excellent too. I've only seen him drop one dolly before TBH.
I think he deserves the second keepers slot. He probably deserves a longer go in the team too.