Returning to the original issue, should
nuanced become a common word? The fact that
nuance is treated as common does not automatically mean
nuanced should be, of course.
Nuance is a noun, not a verb, so
nuanced didn't necessarily have to exist as a word at all, let alone a common one. But in both the News on the Web corpus and the Corpus of Contemporary American English
nuanced actually appears more often than
nuance.
I mentioned that it is used quite often in the Melbourne
Age, and yelnats wondered how often it would appear in the
Sun. I think he probably meant the Melbourne
Herald-Sun rather than the UK
Sun, but both are Murdoch tabloids so it probably makes little difference. Even these papers use the word
nuanced, though they might not carry much writing that could be so described. One example of the word being used is from the UK paper in a report of a football match last February:
Benfica boss Rui Vitoria agreed his side may have been outplayed but had a more nuanced take on proceedings.
He saw much to praise in his team’s plucky rearguard...
All things considered, I think
nuanced should be treated as common in future.