Robert Bowling, aka fourzerotwo, has recently confirmed that there will be no character related customization in Modern Warfare 3.
When Bowling was asked on the social networking website Twitter is it was true that Black Ops’ character customization wouldn’t be included in MW3, he replied “Correct, we [Infinity Ward] don’t do any character customization, all our customization is focused on gameplay / loadouts / weapon camos.”
It seems the important customization sections are back in force with only what the player looks like being excluded from what was in Black Ops.