Turtle, are you saying unless a lens is tack sharp edge to edge you can use most anything, it does not matter? I know your post is part in jest but really to me what results I get from a lens go far past what performance I can get shooting a test chart and whether those lines are really black vs. the background and are sharp right to the corner.
When I want what I consider to be the utmost in sharpness, contrast and color saturation I shoot my Contax G2 kit and 28 Biogon and 45 Planar lenses. But the reason I expanded into Leica mount cameras (I have an MP, CL and Cosina 107 SW with a 15mm Super-wide Heliar perm-affixed) is to go beyond that ultra-sharpness and contrast, especially in desiring more "character" for some of my B&W work. To that end when I researched everything I read and saw it told me that indeed I do NOT want the latest and greatest ASPH lenses, but instead should examine the lenses from the 80's or even 70's on back. After much experimentation and trying many lenses I have settled on a few that have become my favorites as they have a bit more "roundness" to certain edges, yet still maintain an excellence in sharpness and tonality, while often bringing a wonderful tonal gradation and look that is perfect for me. These have been primarily 50mm lenses such as the 50/2 Summicron DR, the 50/1.5 Summarit and 50/1.4 Summilux, late pre-ASPH. (and I recently purchased the 35/1.2 Nokton and find at many apertures it too has same great character that I am looking for.) And lastly the 90/4 Elmar.
Some people are quick to pooh-pooh many of these "older" 1960's designs and they can indeed point out the "flaws" vs. the latest 100% flare-free and better MTF graphs, etc of the newest and latest ASPH lenses. But sometimes too "good" is too clinical, IMHO. I used and sold off a few lenses, since although finding them fine performers, I found them somewhat bland and lacking in the unique character I was after, these included the 50/1.8 Canon LTM, and 40/1.4 S.C Nokton. Fine lenses indeed but not unique or special enough in my PURELY subjective opinion of what I wanted in the end result of my Leica RF work.
It sounds like the 35 Summilux ASPH vs. the pre- may be this kind of comparison and one must decide from what they are after in the end result of the look as to which would better suit them.
To often people equate sharpness or contrast with "better" and that makes little sense to me in subjective photographic pursuits.
