[davidmanze]

I cannot make a Rolex and I haven't seen a Rolex with an adapter to change small hands to big ones. But I own a Nikon converter which has some play

 

I also do not believe in big differences of ML to SLR lenses these days, as soon as the focal length surpasses the mount distance. It's a different story with wide-angles and it's also a different story if the protection glass in front of the sensor gets thicker. I agree it's an important decision for Nikon, but if they decide to change the mount, they will be more far behind than they already are.

 

Not to speak of the handling when you change lenses and have both mount versions, but only one ("super-expensive" will be the normal description for it) adapter. you will just need as long as you need to put a converter or distance ring in between.

 

If they go FF, size or weight advantage will melt away. But an important argument for the solution you have in mind is the easier construction of wide-angles. So let's see what they come up with.

 

Besides a well made bayonet only has no play if the flanges if the bayonet's "wings" (don't know how to name the three segments differently) are not parallel but conical and act like a screw o tighten. Nikon's bayonet is one of the parallel types and needs the springs. If it would be different I could not wobble the lens up and down. 

 As I wrote JoJu, your wings are called "lugs".  As for parallel lugs, I've just been studying the mount lugs, unfortunately I cannot gain good access to the lugs to accurately measure them, they look parallel to my poor eyes.

   Theoretically they should be parallel, any angle to the lugs would introduce wear and would have to be perfectly "indexed" to the mounts locking pin, bringing more problems to the table, as far as I can see my Nikon TC does not have play, even half rotated on to the mount, but I wouldn't bet my life on it........(I would however bet yours) 

 

  Suffice to say that apart from your worn/defective Nikon converter JoJu    ..........  the majority of quality adapter/converter/extension tube owners are in bathing in the "shear glory" that their adapters etc. are giving their photography a new lease of life to their otherwise redundant glass!