Better hardware, not a trash battery, proper storage space, third party controllers to add a proper d-pad, third party devs that stick around for more than a year, proper touchscreen (not resistive crap), etc etc.
Even if Nvidia is putting in a beefier X2, there's no way a Tegra SoC is going to compete with PS4/Xboner visuals, especially when they're putting out "4k" consoles soon. If the portable portion has to underclock itself just to conserve battery life (because we all know Nintendo doesn't know how to properly put high-capacity batteries into their products) than games "on the go" are going to suck performance wise.
I also don't like the lack of d-pad on the controller, even if it is just replaced with "buttons" it's not the same ergonomic feel, so that sucks. Hopefully third parties will come along and make a left side controller that just puts a d-pad back.
I also hope this doesn't flop hard like the Wii U did and have a bunch of huge, long game droughts that will kill the system because Nintendo hates third party developers.
And I also hope they're going to use a proper capacitive touchscreen, not trashy resisitive like they've been using for years so we could at least get proper touch-screen controls on games that may use them.
EDIT: and I really, really hope Nintendo doesn't fuck up storage space with this like they did the Wii U. There's no way in hell modern AAA titles are going to fit on a stupidly tiny 32GB internal storage. 500GB+ or bust, Nintendo.
