One thing I will suggest to MJP, given that it'd be easy to do, is to release shots with various settings for the post effects and gauge player opinion. At the end of the day, you are wanting to maximise appeal based on your audience's preference. If more people will buy the game with less CA, or more, then you want to put that it in. Art leads may take offence that the crude, ignorant masses don't know a thing about fine art, but if people are saying, "yuck, too much blur," and that can be changed with a single parameter tweak, it strikes me as far more sensible to make the tweak.
I'd love to see the effect of different amounts of CA and film effects, all the way from zero to extreme. It may also prove the value of them in adding authenticity and stop the detractors from grumbling.