One interesting thing here is that zooms have got so good that we use older quality primes we seeing only small but real improvements at best at wider apertures, and similar performance stopped down.
And yet lots of users are really interested in these primes. Why? Because we want small light hiking lenses that will be about the same speed and similar or slightly better IQ to our larger zooms.
But the primes we get given are either huge and fast, or ocassionally small but budget. Where are the ones we want?(Not all of us - of course big fast and small inexpensive are important!) The small great but slowish?
The L21 seems to be the first of this breed in the modern era (and if it had been f4 it could have been even smaller). Given how good the budget 28 f2 FE is, imagine a no holds barred 28 2.8! And a modern 180 f4 so I can retire my Apo Lanthar, and a lox 100 2.8 so the collectors of C/Y glass don't have competition from those of us that want to use it!