Here's the thing. I, as well as many other developers, busted my ass to get my app ready in time for launch. Worked late nights, missed some family time, etc. to get the app done for launch. It's in the store, but guess what, no one knows its there, because there is no way to see it unless you know it exists. I don't have money to launch a marketing campaign for it, I have to rely on the tools that Apple provides to get it off the ground. Taking away categories is doing nothing more than ****ing over the vast majority of the developers that are providing software for their hardware. Unless you are in that ~5% to be featured, you have literally no exposure. You are relying on people seeing your app online somewhere, remembering it, dealing with the clunky "keyboard" to search it out by name, and then download it. You can't link directly to it for purchase, you can't even see it in the iTunes Store on desktop.
The device may have been out for 12 hours, but they sent out dev kits ~6 weeks ago, there are somewhere around 500 apps right now. It may not be enough to fill every possible category, but it certainly is enough that there needs to be a way to see them all without knowing the name of them.
Right now, no, there isn't a need for top lists, especially considering how in flux they'd be, but categories are a must.