Two party system - This needs to be changed to a multiparty system. Both major parties suck. There needs to be more parties to choose from and your vote needs to count. Proportional representation is far superior to winner takes all. I would vote if winner takes all was axed. I want my vote to count for a third party.
Electoral college - This is the worst idea to keep alive in the 21st century. Fuck the electoral college. Gore would have defeated Bush if it was up to the popular vote. Now we have turmoil in Iraq for decades thanks to Bush being allowed President. They say your vote counts... What if you voted for the other guy than your state elects? You vote doesn't count.
Citizens United - The biggest pile of shit to ever get approved from the Supreme Court. Money talks.
Election Day - Needs to be a national holiday.
1+2. In theory at least, the US already have a multiparty system. If I where american, depending where I lived I'd vote for either the peace and freedom party, the green party or the democrats. However, first past the post and winner takes all both ensure that all the thir party won't have any chance to ever become president since it makes voting for them as pointless as not voting at all. A proportional or at least a highest averages like the Jefferson Method counting system would give those parties finally a chance to compete and make every vote count.
An alternative would be to eleminate the party system altogether and just vote the persons, without any affilitaion. Winner takes all however would still ensure that the final result ain't really representative of the percentage: If, with 5 candidates total, a candidate would place second in every single state while the others take turns at winning different states, it could in theory end up with a candidate having the highest amount of popular votes yet not a single representative at the end. A multiparty system would however still be needed for the senate then.
3. SuperPacs and the money they make are just used as pure propaganda and diffamation tools. I've yet to see any message produced by them which was actually really constructive or presenting a programm of what the respective candidate intends to do in detail during his period at the office.
Here in Luxembourg, every party gets the same budget, no matter it's size, as long as they can provide a full list of candidates (in our voting system, each one gets as many potential votes as there are ministers (with the head of state being the prime minister). Each party list thus has just as many candidates as well, and voters can give up to 2 votes to a candidate, check a whole party list or mix-and-match as he pleases with the amount of votes each voter has). This ensures that everyone fights at equal terms, while the SuperPacs are really just one step away from giving the power to possibly outright buying votes.
4. Still wouldn't help people like medical staff, firefighters, policemen etc... who, as an unit, can't exactly take a day off. Better would be the right to get 2 hours to half a day free for voting purposes and then return to the job with no legal possibility for your superiors to forbid or otherwise hinder you from going to vote.
I would also add some other thing:
Minimum age for President: currently 35 years, while in pretty much the whole rest of the world it's the same age as when one aquires the right to vote or sightly afterwards, meaning from 18 to early 20's. Wile presidents are generally older than that in every country, the reason is because of the need of experience and rising ranks in the respective party, something that's not necessary in the US as the republican candidates right now amply shows.
Also, much harsher punishments for people or organisations who try to keep people from voting properly through different means like voter caging and misinformation campaigns.