"It's not bad, but it's still pretty bad" is a phrase I can see myself saying. Not sure about the other way round - doesn't really work for me, but to each their own...
I have to say my bad-to-good ratio is probably:
Pretty bad
Bad
Not good
Ok <- Neutral
Not bad
Pretty good
Good
Which I now realize is a little weird to have "ok" be neutral, with not bad/good on either side of it.