I know I made a similar comment in 2015 when it was the top 5 from each of two M heats going through (out of fields of 20+; I finished in 7th in my heat only seconds behind Eric Morris although 58s behind 5th) but I've had a good run, making three other sprint finals that I recall out of four attempts in total.
The idea was to make qualification meaningful for the top end of the field to help prepare them for much tougher qualifications at WOC/JWOC, but this came at the price of not having a meaningful qualification race for the bottom half of the field (unless you were fortunate enough to be in M21 Heat B which was full of DNFs and DNSs). One idea floated in discussion was to have A, B and C finals.