Chuck Dixon is no longer writing for DC.
I haven't seen anything that gives a reason why but on scandaily a lot of people want to blame Morrison and his Batman RIP story.
Some think Dixon left DC because Batman's RIP is effecting his book.
of course currently Morrison has had his worked effect by a number of cross overs that DC has running right now.
If the reason Dixon left DC is because of his stories being effected I think the issue lays more with the editors then his fellow writers.
and with all the errors caused by editors keeping writers out of the loop, I think we will need yet a neither crisis mini-series to "fix" everything.