Every card has a counter, in this case any type of permanent destruction would ruin this card, and the abilities are give at RANDOM, there's no guarantee that you would get a mutant with destroy on your second turn. And besides the mutants from this card has their original stats.
That still doesn't change the fact that there is a
100% garentee that you will be able to use the added ability (because the added ability relys on the target cards color). Not to mention there are far more STRONG abilities to gain than weak.
There is 0 RISK when you use Surgon's Knife/Scalpel... unlike the original mutate.
You could even use the Surgon's Knife as a type of Lobotomize... Cast it on Deja Vu, Maxwell Demon, FFQ, Fallen Elf, Armagio, Mind Flayer, Pest, Oty or any of the 12 nymphs to get rid of their primary function.
If it was more like Chaos Power giving random stat buffs I could see your card as being balanced (the ability cost could be 3 entropy per).