It's been discussed before, and I think the upshot is that it can give an advantage to k/m players against the majority of players with controllers. AFAIK the only console games that offers k/m control are PC derivatives anyway.
In future, please ask questions in either the Ask the Devs thread or for answers from the community in the Ask A Question thread. Thanks.
Haze FAQ - please check first if you have a question about Haze.