Extra weight... But even with an extra 200kg worth of fuel (I don't think it's that much - considering the fuel-loads in 1988 were 155l/race, and current cars already carry about a third of their load), the cars still weigh around 700-750kg (including some teams who won't handle KERS' weight-increase). And yet we have endurance-cars racing for hours who weigh over a ton, with lower-specification brakes, tyres, aerodynamics - and yet they're also very safe.
The only change would be for the drivers to find a slightly bigger compromise between a full-fuel setup and an on-fumes qualifying setup. You could have a faster car in qualifying and the last part of the race, or have a stronger car in the first two-thirds of the race. If anything, those variations will lead to more of a spectacle.
Rob W wrote:Refueling as it is now allows for cars to complete the race driving the highest possible speeds when on-track. Using 'no-refueling' as a means to either slow cars or to get rid of the 'passed in the pit stops' scenarios is missing the point. If refueling pit stops are indeed affecting the cars then shouldn't we really be asking why the tires are so variable in their performance over a stint? Or why there are two compounds on offer and teams so so often getting the wrong ones for the particular time in the race (why not just one? - the same for everyone).
I believe you mis-read the comments left by some regarding under-fueling for the whole distance. I think they meant under-fueling, hence forcing teams to develop KERS systems to compensate as a constantly-available, "second engine" sort of power-source to save fuel - which would both fit in with the FIA's green message, and develop technologies that are road-relevant.
The way KERS is currently going to be implemented is, I agree, completely daft. However, if you look at it as a constant source of extra power, it is a tool that can be used to make the cars actually faster, while also improving their gas-mileage. So yes, teams could fuel, say, 80% of what the gasoline engine needs to complete the distance, and in return, compensate with KERS - and ultimately, be able to attack hard for the whole distance.