Thoughts on whether or not this and Swirling Gale have a place in the skeleton or if they should be left behind? They're both ways of using Discovery for mass creature damage.

I think we only want one type of effect like this. Currently we have Swarm's Hunger but now that has become the aggro archetype that doesnt seem as fitting anymore. I was thinking about taking over from it but we also have the small toughness archetype in red so I'm not too sure. I feel like maybe we should have something in blue to bounce, since is the archetype that could benifit most from that sort of effect.

I feel like this one is more meaningful of a consideration than Swirling Gale, which is more limited and not a particularly important thing for green to be doing.

The only objection I really have to Swarm's Hunger is that it appears that the prevalence of the bottom of library theme is being questioned, so maybe that aspect of it makes it a weak pick.

You have a really good point that Swarm's Hunger really goes against the aggro archetype. I'd suggest putting this in and actually taking out Swarm's Hunger. And Swirling Gale can be left behind with no sweat as just not important or fitting.