Why drive a Ferrari which has engine from an Lada when you could get the Real Experience with only a little more time invested? Develope the PC-oriented UI - it's a no brainer...
i'd rather drive a niva than a ferrari, straight up.
i'm in the minority in that even though i played Oblivion and Fallout 3 on PC, i really liked their UIs. they were very clean and organized, which matters a lot to me when i'm trying to find something. it would've been nice to be able to remap the F1-F4 keys, yeah. i would've liked a bigger font, and Morrowind-style ctrl/shift-clicks to drop single items and stacks (which if i'm not mistaken Fallout 3 addressed, though it's been a while since i've played it so i can't really remember).
more than that, though, and in addition to using the mouse - i would've liked to be able to use wasd to navigate through them, using a and d as alternatives for the controller shoulder buttons (bumpers? triggers?) and w and s to scroll up and down. it's irritating as hell having to click an icon when the UIs are clearly designed to be able to flip through the tabs.
i don't care about grids or whatever, lists are just fine (though it would be nice if equipped items were listed at the top of the inventory and/or moved to their own tab, so as not to take up space randomly), but at least make it faster to navigate. our left hand isn't doing anything in menus when it could easily be.