The most important bit is a point I haven't seen anyone make before: Gerrymandering worsens deadlock because it locks parties into current coalition. Once the lines are drawn a party can't toss out Group A out of the coalition to make room for swing voter group K because A has been gerrymandered in and K is split up. So the folks in group K get fed up and stop voting since no one's willing to listen to what they want. Meanwhile the party can't change its position on an issue no matter how much it's getting hurt by it with the swing voters, because the core coaliton members dominate the primaries.
Agreeing on the problems is easy. Figuring out what to do about them is hard. Here's my take on Grim's proposals:
Repeal 17th Amendment and have Senators chosen by state legislatures again
Hell, no. Right now I have some elections on Federal issues and some on state ones. Change that and all my state races become referendums on the key national issues. It's hard enough to get them to talk about important local stuff now.
Rewrite 14th Amendment to restrict federal jurisdiction to the original issues
I'm in favor of increasing Federalism. Altering the 14th is going to freak a lot of people who'll automatically interpret it as wanting to re-legalize slavery. Possibly we could pass a new amendment declaring certain things to be under state jurisdiction? That'd be making formal some of the unspoken parts of the 9th and 10th Amendments, which have been mostly ignored lately.
End Gerrymandering by electing all of a state's Representatives at large
Just taking the top N vote-getters leads to all sorts of bizarre results. Good candidates will step aside to avoid knocking out a fellow party member. Loonies will get in by random chance. You're setting up for a situation where the top 3 candidates get 80% of the votes and are outvoted in the legislature by the 7 clowns who got the next 12%, with 8% going to also-rans. If you don't want single-member districts we could do proportional representation, as a nationwide vote or by having PR within each state.
I'd rather have non-gerrymandered districts drawn through a simple exercise: Each member of the state legislature can submit a plan. The length of the district borders in each one are measured. The one with the shortest total length goes into effect. Then each Congressman will still have to get 50%+1 of the vote without getting to pick his voters.
Create a new agency for hunting down leakers
Please, not an agency. If the current problem gets solved the agency won't go away and eventually we'll have full time investigators hanging around to see if anyone mentions his job title in public. We've got laws, let's use them. Start by locking up reporters until they reveal where the info came from, like with do with uncooperative witnesses to other crimes.
Congress should do its oversight function well
And apple pie.
Reform or quit the UN
Reform demands are just a way of delaying quitting. The problem is that a genocidal tyrant can be a full member. There's enough members like that to prevent change. It's a lost cause. I'd favor quitting now. Unfortunately there's too many people so attached to the ideal of the UN that they won't give it up without a fight. This might be more trouble than it's worth.
Penalties for failing a specified list of duties for each federal office
Most of the offenses we see today are already illegal. I'm afraid rigid job descriptions would make things worse. In particular it would make office holders unwilling to set aside one of their listed tasks to support another office in dealing with a higher-priority problem. This is already a problem, visible in the response to Katrina. Let's not give them threats of jail they can use to justify even more inflexibility.