I definitely think it should have a swivel screen.
The only complaint about swivel screens that seems valid (but solveable) is that is that on some models they don't fasten to the camera well, and if you're not swiveling they can flop out. That's bad - but it seems like a good design shouldn't have this problem. Heck, we're talking about a dslr here - it's not like size or weight is at a premium, put in a good latching mechanism.
If you're a dslr snob, you're definitely not using liveview anyways. You're using the viewfinder.
The only thing you use it for is navigating menus or reviewing pictures. If you've ever tried to review pictures via the camera screen, you know that a picture which looks bad on the screen can end up looking good at full size on the monitor, and visa versa. So if you lose a few pixels in exchange for the rotating screen, it's not like it's going to make much of a difference anyways.
So what I'm saying is - the screen doesn't do any primary tasks on the dslr anyways. Usually the argument against an articulating screen is that you'll lose a few pixels of resolution, but that isn't going to make or break anything you're doing anyways.
But an articulating screen makes liveview useful - in situations where it's impossible to use the viewfinder, you can finally actually use liveview for something. If you need to hold the camera over your head, if you need to put it down on the ground, to your left or right, put it on a tripod, remotely trigger the camera (you could be standing in front of it!), start a long exposure going without touching the camera...these are all things that liveview + articulating screen can let you do when it's impossible to use the viewfinder.
