In the Leicasphere, one constantly sees arguments to the effect that a live view function should not be pursued with M cameras because it violates some tenant of "Leica M photography."  Nonsense.   Over the last nine decades, Leica has pursued all  of the same features that live view offers - only through clumsy optical and mechanical workarounds. So why discard, out of hand, technology that could streamline M cameras and increase their usability?

1. Accurate framing. Leica has never built a camera with accurate and infinitely adjustable framelines (field size and parallax correction).  This appears to be an inherent limitation of having framelines projected from etchings (either holes cut in metal masks or lines printed on glass masks).  As a result, the M viewfinder (as configured on the M8, M8.U, M8.2, and M9) has three key limitations: (a) showing frames for six lenses; (b) showing two sets of frames at a time; and (c) precise framing at one distance only (1m or 2m, depending on the camera). For situations that allow it, live view would overcome each of these limitations. Of course, changing to projected LED framelines would allow it too, but that would evoke even wilder protests from the men wearing Tilly Hats.

2.  Leveling.  One rather terrible aspect of the optical viewfinder on M cameras is that it does not provide a good reference for leveling the camera.  On an SLR, one would use a grid screen like a Nikon type E (or on newer cameras like the D3, using an artificial horizon shown on the rear screen).  The only current option for Leica cameras is the Universal Finder M with its integral bubble level (bulky, expensive at $800, and only amenable to leveling with the camera held in "landscape" orientation).  Live view on an M would allow the user to see a grid superimposed over the live image, removing orientation surprises when the lens is 21mm or shorter (M8) or 28mm and shorter (M9).

3.  Accessory finders.  Does anyone actually like these?  For that one shot taken on vacation with a 21mm or 15mm or 12mm lens, it's usually necessary to carry an accessory viewfinder.  These finders are expensive, they create snag-prone projections on the camera, they are usually fairly distorted, they sometimes get pushed off and/or dropped, and like the M viewfinders they supplement, they usually have framelines of extremely limited accuracy and nothing reliable from which to level a camera.  Did I mention that they block the flash connection too?  Some flashes do cover angles wider than those shown in an M viewfinder (the SF-58 covers 18mm; some Canon/Nikon/Matsushita flashes do 14mm).

4. Right-angle viewing. An upward-pivoting LCD would be a great replacement for Leica's eye-straining right-angle accessory finder.  It would also allow very facile waist-level (or low-angle) shooting.

5. Macro/long telephotos. The Visoflex - an unabashed kludge for six decades - could finally be put to rest with live view and some form of focus confirmation (well, even that may be unnecessary if the screen went to a modern pixel density).

6.  Effectively focusing other lenses adapted to M.  Wait, did I just write that?  Never mind.  You never read it.  Forget that GF-1 and EP-1 users are doing that.  They must be insane.  Seriously, though, insecurity about the performance of non-Leica lenses - particularly modern, well-corrected SLR lenses - may be a topic of great concern in Solms.  This would be an excellent reason never to introduce live view on any M camera. So ist das Leben?

So at the end of the day, it's hard to rationalize an ideological reason not to incorporate live view.  Perhaps there are technical reasons, but the unwashed masses of engineers at Nikon, Canon, Panasonic (who incidentally makes live view Leica compacts), and Olympus have managed to do it.