Nah, PU is actually super strong if it could be used multiple times, especially since it depends on the creatures in the field. You could essentially have 10 creatures with over 20 attack just for 40 . The standalone card itself isn't so strong, but the ability to give multiples of each creature gives you ridiculous field advantage. And that is why "my" nymph dies eventually after creating a few copies.
well, you COULD create a hell of an army with something as simple as aflatoxin + fallen druid. and the druid costs 5
to play and 1
to mutate and has a stable 3/3 stats. there's the random factor, but IMO it's as overpowered as having a 9
1/2 card with a 4
PU ability. you need to:
a) spend 9
to play it
b) spend probably something around 10 non-
quanta to play a really strong card
c) spend 4
per turn to duplicate it (or the nymph)
d) hope your opponent doesn't have an offensive shield, oty/scarabs, antimatter, aflatoxin/parasite, owls eye, shockwave, lightning, lobotomize or even quint.
maybe it should have 1/1 stats and 1/2 when upgraded, like the nymph queen, but I still don't think it's impossible to have a PU nymph (we have an antimatter nymph, don't we?)