> If 80% are good submissions it’s a useless filter and should be dropped.

How did you arrive at this conclusion? I can easily imagine that this process is so laborious that plenty of people don't even submit anything. Like the person who wrote about this on reddit. -- Now what reason would we have to think that the people who don't want to go through the process would also be 80% good? This may be a very valuable filter for Canonical!