We hate dithering and aliasing just as much as you I think. Hardware 4xAA on the Xbox360 is nice for a lot of things - it did take us a while to get the most out of it (E.g, refactoring the renderer quite a few times).
Shadow aliasing doesn't really have anything to do with the generic framebuffer resolution or aliasing quality, but having the game run with 4xAA in the framebuffer is kind of rubbing in any other visual quality problems there might be.
We don't like ugly things, so we fix them before shipping.
We like 4xAA. Due to the alpha-to-coverage feature on the Xbox 360 GPU, it's one of the key reasons we can render a lot of "alpha test" foliage like trees and bushes without them starting to shimmer or dither (as alpha-to-coverage with 4xAA effectively gives us 5 samples of alpha "blend" without actually using alpha blend). Of course that leads into a lot of interesting ways how to get the the other "standard" z-buffer based rendering schemes to not alias, but let's not get into that discussion right now.
The game is locked to 30 FPS (well, except menus, manuscript pages, etc which run at 60 FPS). All cinematics are guaranteed to run 30 FPS (as we actually background load the next location, in case there's a location change). If you saw video tearing in the published press material, it's 99% due to video sync issues (E.g, PAL video cams or 59.97 Hz vs. 60.00 Hz screen update).
While playing Alan Wake on a Xbox 360, if the game framerate drops below 30 FPS we resort to screen tearing (same idea as Gears of War uses).
We're right now just fixing bugs and making sure nowhere in the game would the framerate never dip below 30 FPS. I know there's still a few heavy locations in the game where we resort to dipping below 30 FPS, but we're working very very hard to get all those solved.
