A good season in European Karts (F.Super A) is as competive as F.Ford any day. Look at Trulli, Button & soon Pantano-Alonso, Karts to F1 in 25 races! Alonso only did something like 16 car races before he tested for Minardi last year. I think the number of races doesn't matter, I just think Kimi needs to do a season of at least F3, F.Atlantics, Indy Lights, F.Nissan or F3000 first.
Also, I don't think that GB F.Renault is as competitive as Euro F.Renault or even Italian F.Renault. If he blows Massa, Grassotto, Antinucci, Schmidt, Winkelhock and Del Monte away, then I might change my mind....