Julian, dont forget the difference between the current F1 drivers is pretty slim. There is also something like a momentum and the actual package which helps or doesnt...
Generally TIMO is right up there, from the ones you mentioned I would say he would beat MARK(even though on a good momentum..) and KIMI(on his current, still less than his best, momentum..) on equal terms 2 of 3 times.
I would say 3 stand out just that little bit - and they are FERNANDO, LEWIS and SEBASTIAN.
Last year FELIPE and ROBERT would have been close but they are fighting with their package now.
JENSON could get there if he continues at his current level(and great momentum). I could now name TIMO as No.5 but in fairness he wouldnt be the only option...
I think he is a bit unrecognised with his extremely smooth driving(=why he didnt get any heat in the prime tyres at Bahrain...). He would probably have won the Sepang GP had it been restarted. Dont forget the immediate excellent impression he left in the Jordan and then his domination of GP2.
Re.your A1 example - If a driver on some occasion looked poor that would be human and doesnt mean but nothing...
