Swarm of the Century definitely shouldn’t be black-green hybrid. Monogreen shouldn’t get the ability to churn out flying tokens. Maybe make the tokens blue and have it cost X(wb)U.
Some interesting remakes of existing M:tG cards, for sure… as well as a few ‘new’ cards among the many revisions (i.e.: the ‘Loopty-Hoop’ looks more like an under-costed Kitesail than anything).