I don't see how you can come away from Singapore believing that Ferarri were the strongest unless you've the capacity for some serious delusions. Two cars. One car was a DNF after being stuffed into a wall and the other came in 13th after the team failed to address an already-identified and still-unaddressed flaw in its pit management system. How is that strong?
For me, Renault were less strong than they were lucky (being satisfied of no foul-play). Considering that 50% of Renault painted the barriers with "ING", I don't think they were strong overall. The 50% of Renault that did finish wouldn't have been where they finished up being at all but for the timing of the safety car period. The safety car period with its ludicrous pit rules only serves to shaft the race, really, and screw the result up.
Pound for piston, I think Williams was there on the day. Both of their drivers finished(!!!) higher on aggregate than anyone else, as far as I can tell without breaking out a calculator.