Strawman, much?
That's not what people here are (mostly) saying.
What they are saying is that Leica may have gone far beyond the point of diminishing returns.
Mandler's v. IV Summicron was already a spectacularly competent lens. The Planar has a slightly different mix of characteristics (including slightly less curvature of field and slightly more linear distortion) and overall is about equally as good at about 1/3 the price. The Summicron AA is a bit better than either in most respects but it costs TEN TIMES as much as the Planar.
If you are racing F1 or MotoGP, it is worth paying 10x as much for a 2% advantage. That is the difference between possible victory and consistent defeat.
If you are taking pictures -- especially handheld, as the Leica M is designed to to do*, especially with a focusing mechanism as crude as a rangefinder, and of three dimensional objects rather than brick walls or test charts -- a 2% improvement will almost always be invisible. Even if the difference is visible, it is unlikely to matter. There may be special cases that one could formulate where this new lens might offer a useful improvement, but those special cases will be few and far between.
Leica is focusing intense design expertise and effort on improvements to a show-piece that will not improve peoples' photographs, or even markedly expand their photographic tool kit. Such an effort might be described as corporate self-gratification. Not that there is anything wrong with that. Right?
*If the M was designed to be used on a tripod it would (1) have live view so that one could actually focus accurately (and not just at the center of the image); and (2) it would have a mechanically stable tripod socket, which it emphatically does not.