The "unfiy colours" doesn't always give the desired results, if, like the Commando Elite chest piece your armor has some fine detailing (a yellow/gold piping effect down the flanks in this case) in another colour to the main scheme you may end up with some unexpected results. When I unify colours when wearing the Commando Elite chest piece my boots end up being yellow and white instead of black and white, which is the main colour theme of the armour I was aiming for. Yes, I know I can just unselect the boots for colour unification. But armour dyes would be a handy way to pimp your gear in the way you want, rather than the way Bioware has seen fit to give us so far ( maybe Mr Lucas et al don't want to see pink attired Darths, I don't know)
They would also provide BW with another money sink for the age old problem of inflation in MMOs.