Well, first thing they need to do is get rid of DRS and the reliance on an excess downforce. Hopefully that means this years cars are a one off and we're back to mechanical grip. Yes, it'll make the cars slower initially, but with the reintroduction of ground effect they can seriously simplify the front and rear wings and also remove all the god awful appendages that have sprung up all over the cars. T wings, bargeboards, D wings, monkey seats... This should also allow them to run closer as well.
I'd also consider cancelling Ferrari's $100'000'000 'historical' payout along with the any other payouts that aren't for merit each year and either distribute it among the teams that finish 4th or lower in the Constructors Championship.
A nice approach for the fans is not to DCMA the crap out of any clip of F1 taken from the stands. Something seems to be happening that way already. Teams being allowed to show video from the paddock, pits and pit lane now. Not the track, but it's a massive change already.
FOM also has a massive archive of footage from the years, how about open it up a little? We see the odd old race on Sky, but would be great to have access to entire seasons. Maybe a custom streaming service that who knows, could also one day cover the live F1 weekends too...