Arriva stevenage VDL 3782 by Rob Elloway, on Flickr

It's up to the (again, useless) marketing team to do things like this, and yes, it would be a fast and easy way of rolling out the new brand.
If I had my own way the fleet would be smartened up as a priority with the Arriva brand replaced both inside and out, removing any references to defunct MAX and Frequenta brands and changing the vinyls on the transitional Journey Mark liveried vehicles too.

It's not on an "as and when" basis, as there are always at least two vehicles in for repaint at a time.