Watching the classic race replays on f1's YouTube channel recently I've been struck by the fact most of them have been wet weather/interchangeable weather. It's not necessarily the case that wet races always produce a classic race, but the ratio is certainly higher than dry races.
A while back Bernie in one of his typical off the cuff comments suggested sprinklers as a means of spicing up the show, Murray Walker even jokes about it on commentary in one of the races, while I'm not sure that idea has any traction (pardon the pun), there does seem to be merit in reducing the grip of the cars if we want great races.
How else could it be done? Just lowering downforce wouldn't necessarily work as the f2 and f3 races aren't so much better overtaking wise. Harder tyres? Narrower tyres? Crossply tyres? More power to make them rear grip limited? No engine throttle maps (i.e. Just a linear response from the pedal)?
This is all just blue sky pondering as it'll never happen.