s/\([Ee]vil\)ness/\1/g
s/\([Ee]vil\)ness/\1/g
For an analogous example, try replacing "lightness" with "light" in a discussion about color and see how much sense the text makes afterwards.
Yeah, that'll get really weird really fast, what with "lightness" being about weight and not colour, and all...
Can't even complain that it's a neologism and kids these days with their bad grammar; "yfelnyss" would appear to predate the Normans.
Nor is "evil" in the noun sense a great synonym for "evilness" in the noun sense. "Evilness" denotes the state of being bad, while "evil" denotes the badness itself. Evilness is the correct word here. Using "evil" would have been, if we want to be really pedantic (I hope I can safely assume that we do), been mildly nonsensical.
[EDIT:] However, I can't agree that TFA is about "the state" of feature branching, or really even that feature branching is an entity that can possess a state. According to TFA, feature branching is bad. That's an intrinsic property, not one that feature branching will be able to overcome with appropriate prayer and reflection.
This is usually the case when abstract nouns are considered evil, so "evilness" is usually poor diction.
Indeed, we could not say "the black of feature branches"; it would have to be "blackness". Something that is black (adjective-wise) doesn't "have black" (the noun); it "has blackness".
The word "evil" doesn't conform to this restriction; "the evil of feature branches" is fine. Therefore "evilness" is just superfluousnessitude.
The word "bad" is color-like. We need "the badness of feature branches", not "the bad of feature branches".
But "evil" functions in such a way that it can substitute for "badness", and therefore for "evilness".
When we say "the evil of feature branches", the grammar is very similar to "the hypocrisy of using feature branches" or "the iniquity of using feature branches" or "the stink of feature branches" and such.
None of these words require an additional suffix; "stink" need not be worked into "stinkiness".