An alternative is to stick to parochial genre standards of excellence, that nobody else cares about ('this is a local sop for local people'). Don't get me wrong, I think these standards are important. For example in SF, there is a sophisticated readership who already have a clue about faster than light travel and what its physical, political, economic etc implications might be. A story, no matter how well written, that is just a variation on the Twins Paradox won't cut it by our standards. Quite right too. A writer in a genre needs to understand these local standards, and take them into account.
The problem with this is that it's not going to win any converts, and it isn't going to improve the standing of the genre within the wider society. Do we care? Probably we should. If SF had higher status and more clout, we might get more and better stories.
I have a third suggestion about how to spot 'good' genre writing. That's to do with the way we use metaphor. The most typical way to use it is to point up a particular characteristic. So we say 'Achilles was a lion', and we mean to zoom in on some characteristics (he was brave, magnificent, aggressive) eliminate others (he wasn't timid or tiny). The metaphor is a tool of precision.
But another use of metaphor is expansive. So in genre writing we can say 'What if a man was a wolf?' and the wolfman has the full package of wolvish characteristics. He has four legs and claws. Using a metaphor expansively can lead our minds into interesting places. Are we a bit envious of the wolf man? Is it a curse or a blessing? Can he live within society?
Only non-realist fiction can really get hold of metaphors and use them to stretch our minds. I think we should celebrate that fact.
