1) Switch from winner-takes-all to approval voting.
Largely eliminates negative campaigning. Counteracts drive to partisanship.
2) Restore Fairness Doctrine
https://en.wikipedia.org/wiki/FCC_fairness_doctrine
3) Publicly financed campaigns
Greatly reduce effectiveness of pay to play strategy.
The way it was justified was that there's a natural limitation on the amount of spectrum, so the government has an interest in ensuring that not all channels on that spectrum are Fox News.
The spectrum gets more irrelevant by the day as more TV moves to cable/Internet, and people in general get their news from the likes of Facebook instead of TV. There's no natural limitation on the number of channels on cable or Internet, so the government trying to police speech there would be ruled unconstitutional.
Your #1 suggestion is doable, but would require something just short of a successful revolution to pull off. #3 likewise, you'd need a constitutional amendment due to Citizens United.
#3 Public financing reforms have thus far been a bottom-up effort.
As for #2, we'll see. The backlash to social media is pretty intense. There's an opportunity in there some where.
Instead of ads have the politicians debate on live TV to express their political views. Post the debates online for everyone to watch at their leisure.
Leave the measures/proposals to us to research; in Colorado we get an excellent voter guide that clearly explains the measures, including pros/cons. That's all I use.