to make the cost balanced i think we never get the right cost^^
the cost of this card must be one
for every creature is affected
unupped=creatures enemy control-creatures you control
so 2
is fair because you have to have 2 creatures less than the opponent to get advantage of this card
upped=creatures enemy control+creatures you control
so 5:entropy means it is fair when enemy has three creatures and you have 2 creature
also not all effect are same powerfull to all creatures
a lighting is unuseful on a firefly queen while a lobo is devastating
a lobo is useless on a
dragon but a lightning kill him...
i believe it doesn't matter so much the cost and should be cheap as is because you have to work hard to get some advantage to this card!