All the suggestions so far are about what topic SAC should be, which I find interesting, since the first one could be anything you wanted. So if it was like the first one, all of the suggestions above are implemented (other than maybe disqualifying isekai).
Something I'd notice last competition is a rather small portion actually hit the word count minimum requirement. Maybe lower that? Alternatively, increase the length of the competition so people have more time to write.
Another thing to note is that reader count has the slight issue in that readers mean anyone who put the story on any list, which includes a dropped list or a about to read list. If the beginning seems extremely promising or clickbaity, but the story becomes a shitshow later or fails to deliver what was promised, people tend not to actually just remove it from their reading list, but rather put it in a dropped list somewhere. Also, if the premise seems interesting a busy user might just put it on a "to read" list without actually even reading it, which makes the competition more like who can come up with the best synopsis and hire/draw the best cover.
One way to get around with that problem would be to vote, but that potentially runs into the problem of having a really low percentage of people voting. At least this way, the voters actually support the stories they vote for, instead of a "dude this story sucks, instant drop, but because of how readers work, it still counts as a vote for some reason."
