It depends on how you want to count better, and mpx. Yeah you need 4 images perfectly alligned to sample each color at each subpixel location (assuming your lens + aperture + shutter shake + movement allows you to have that much resolution) and I agree that you won't see a 4x improvement in resolution since the thing we compare too isn't a binning of each Bayer subpixel into a single final pixel, it's the result of a complex interpolation scheme. Then there's the issue of what we mean by resolution. Are we talking about MTF curves? And in that case is it black and white alternating lines, or is it colored ones?

I would much prefer for these pixel shift modes to produce an image where each pixel has an RGB value associated with it, rather than yet another Bayer image that's just bigger.