It'd probably make more of a mess trying to adopt a common livery now, particularly as the closest thing they have now is a dull grey and probably not a good choice. A lot of the sub-brands are pretty long standing things as well in some form.
I agree they went too far with Rosso though - it was as if everything had to have its own brand. There must have been nearly a dozen of them, plus the rarely-seen core Rosso brand changed from the old red and white to yellow for no real reason, but the main service actually in Rossendale became purple. I think they could have had some route branding without making it so complicated.
