Do not want.
I literally have no idea where this Daniel Riccardo kid came from, why on earth does he deserve to replace any of the drivers on the STR lineup? Buemi and Alguersuari are, though a bit mistake prone sometimes, especially the former, a good lineup that will bring home the points. What does Riccardo have that these 2 don't? It pains me to see STR talking about replacing one of their drivers with this guy who hasn't done anything special rather than being within a tenth of Vettel's pole time in the young drivers test. It only helps to prove that STR is the worst place to have a F1 career, because you will just never be able to prosper, the team will eventually get tired of you, and you will get replaced, unless your name is Sebastian Vettel.
And now he's going to replace Karthikeyan. Unless he's bringing in money, I don't see this as a good idea. Nevermind Karthikeyan's poor effort in Valencia, that was an all round poor race for HRT, probably their worst race since Bahrain last year. For most of the season, Narain has been reasonably close to Liuzzi, given him not being in F1 in 5 years. And his experience will move HRT forward in development of the car, they don't need a noob who doesn't know the car yet, a car which is tricky to drive, to risk running up repair bills.