I'm not a big fan of elections, and I reckon there are good arguments for other ways of choosing leaders such as random selection or the hereditary principle. I'm also usually not one to promote any expansion of the federal portfolio and would just as soon see the federal government abandoned.
That said, if you're going to have a federal government with elected officials, it doesn't make a lot of sense to me for those elections to be run by county registrars and state secretaries of state with a wide variety of registration requirements and voting methods and allocation of resources among precincts. The helter skelter system in place today invites partisan abuses, fraud and voter suppression. A uniform set of standards for registration, ballots, voting systems, and allocation of voting machines/polling places among precincts would be reasonable for federal elections and would go a long way toward keeping voting and the counting of votes honest. It is possible that a single party could expropriate the process and turn the entire system into a farce, but I reckon it would be much harder to do this on a national level than it is on the local level. Besides, we're pretty much already there only with two parties with a monopoly on the ballot.
I favor early voting so that folks don't have to stand in line and so foul weather doesn't swing elections one way or the other. I can't vote early where I live, so I have to get to a polling place tomorrow come hell or high water. I reckon that voting booths and polling places should be distributed such that the ratio of voting booths to voters is pretty much the same everywhere (except in rural areas where you'd want to avoid having folks travel too far).
I favor loose registration requirements that allow folks to register as late as possible, even on election day. Hell, let's make it automatic for high school seniors and for soldiers and sailors when they sign up for school or service. I'm not too worried about folks' voting under assumed names, because both parties can play that game. Suppressing the votes of actual would be voters is a very much worse problem.
I used to be in favor of making voting more difficult, but that was just a way of undermining democracy. I'm still not a proponent of democracy, but I'd rather be up front about my position and let it prevail or fail on its merits.
I'd be interested to hear arguments against federalizing federal elections. It has never bothered me to be wrong; if it did I'd be a wreck.