Simple is best, otherwise you go to the extreme of ornate liveries. Some more effectual than others, but the costs of applying such liveries must be astronomical. Remember the flack that BA took when they revealed their ‘World’ liveries.
What is a livery for? It serves no purpose in the air, However, on the ground, it identifies to the general public/passenger a presence. It may not look pretty to the aficionados, or the aviation photographers, but it gets them noticed by potential customers.