Something good to note: This Nymph is definitely worth the upgrade! and it does so without breaking the standards of balance to achieve that end.
Actually, both Nymphs are interestingly different from each other...
Clear Nymph is more Quanta denial efficient. If the permanent/creature is destroyed, next turn you won't be able to keep on denying, and the higher casting/ability cost don't help that.
Void Nymph is more useful along with devourers, as PC/CC on a stick+denial meanwhile.
I like how this works, and how the names fit well (Clear--->No more quanta | Void--->Emptiness, no creatures/permanents/quanta).
The only problem I see here is coding this being used in flooding. I guess draining
+
will have the duo-draining problem we saw in ZBlader's Duality Series (
http://elementscommunity.org/forum/index.php/topic,19516.0.html).