Yes, I agree it will be hard to be satisfied with single shot captures when I upgrade to a new back, unless the interpolation of the newer backs is better in single shot mode than my Jenoptik Eyelike Precision M22. I will keep my ancient 22mpx tethered-only 25 ISO screenless back just so I can still use the multishot when I shoot a still life job that includes fabrics, architecture, if I need a huge file, or if there is a lot of red or overlapping red and greens in a shot. This is the most obvious time when a 4 shot capture looks much better than an interpolated single shot. I shoot a lot of food, and if I have strawberries or other reds in the shot I will try to use 4 shot mode for that. Similarly if there is a green leafy salad with red chilli or other red bits overlapping the greens the quality of the overlapping edges is vastly improved - no harsh dark halo or outline like in a single shot. 4 shot mode works fine with my Contax as long as you shoot it in the 2 sec self timer mode, because the mirror flips up then the shutter fires 2 seconds later, after the mirror vibration has settled. 16 shots work perfectly for me with a Sinar P2 and Schneider digitar lenses with their electronic shutters, but often need a bit more sharpening in post. I am aware the new cameras like the Hy6 and Hassy can keep the mirror up for the entire process, so in theory a 16 shot capture with one of these cameras should be no problem.
Ben