Forgot unstable gas for Air. Also, I'd drop air down to medium, since wyrms suck that much.
vultures need virus/plague, so they're not really that reliable...arsenic is definitely reliable, and poison is just as reliable with/without extra poison. If the opponent has 20 poison counters on him, poison will still make it 22, you're like saying that ash eater isn't solid offense because it needs phoenix to effectively kill the opponent, while ash eater isn't solid solely because it sucks. By the way, I think poison is reliable because, since dragons are up there, we're assuming the opponent doesn't have healing over time, and therefore you can whittle their HP down to 0 with poison as long as they don't have purifies (added reliability from being hard to counter/destroy/mitigate).
Wait. Must "solid offense" things be able to be countered by "solid defense"?
Charger(unupped) and Momentum don't really do much, I'd put gravity in medium too.
A time rush does pretty well because of precognitions, deja vus, and scarabs/ghosts. Also, time nymphs are 1337.