The most simple thing the FIA can do to reduce downforce is to set a god damn limit, its not that hard to say "this is how much downforce your allowed, now use it..." Forget constantly banning new devices, theres no point.
Also with this damn engine homologation to stop uncontrollable speeds and the apparently "pointless" process of increasing maximum revs..... SET A MAXIMUM REV LIMIT!!!!
Nay, I would strongly oppose both of those, whilst they are both workable solutions, I feel they take away too much... individuality from the teams. I mean if they all have the same power in the engines and the same downforce, then it would take away one of the main techy attractions of F1, the teams' constant battle to get ahead of each other (and given Toyota and Honda are strongly opposed to full engine homoglation, how would they respond to that?).
I think eventually you'd have all the teams with cars that looked the same (once the most effecient solution had been worked out) and, although it would be fairer on the drivers if their cars were more equal, I feel it would take too much away from the sport.