It depends on where you live.l as to whether ice is a corner case. It's a corner case for Bay Area residents, for sure.
Where I live (south of Chicago), icing is a frequent event. I've lived here 8 years, and I've probably had to chip ice off of my windshield 100 times, and I've gone at least 5 days in a row where I've had to free the sliding doors on the minivan using shoulder-checks or window-frame yanks. At some point nature wins, of course, but why put the Tesla at a disadvantage?
What I'm pointing out is that all appearances suggest the flush door handles shown on the Model 3 will become unusable when coated with a very small amount of ice -- way less than what would be required to create a problem on a conventional door handle.
That's a design fail in my book.
The parts bin handles used by Toyota, Honda, Ford, et al have solved this problem by allowing you to get your hand behind the handle to give it a hellacious yank. When you do this, the ice falls off of the moving/flexing parts of the handle, and you're on to the problem of actually opening the door (which may be frozen shut around the weather stripping).
Their solution to this is boring but very effective:
http://images.hgmsites.net/lrg/2009...n-i4-auto-le-natl-door-handle_100242593_l.jpg
I hope Tesla has some sort of clever way around this problem that I haven't thought of. The obvious ones (The Model S's retracting door handles and the Model X's robot doors) look like budget busters, and having a heated door handle seems like it would cost time and kwh. I think I'd pay extra for cheap door handles like the one in the picture above.
P.S. My minivan has an electronic latch on the liftgate. It works fine in snow and ice. The switch is under the license plate overhang where its protected from ice buildup, and where you can give it a hellacious yank when you need to. Our Prius used something similar, which so.worked well. Again, it was protected from ice buildup by being underneath an overhang, and it gave you pretty leverage to yank open the door. I've never had a problem with either of these systems, but neither one has a lever which swings out through an area that's likely to be ice-encrusted a couple of dozen times a year.