Things that could make suit customization usefull..

[GTOne2Three]

- you can create and edit decals for your helmet like Forza.
This could be practice for a livery editor for PD.

-allow other players to see a close up of your helmet as it rotates on your driver profile.

 

[sumbrownkid]

A cool nifty idea would be a manufacturer's logo on your suit changes automatically when you switch cars.

 

[Snapey]

-
allow other players to see a close up of your helmet as it rotates on your driver profile.

Biggest innuendo of the week! Back on topic, a helmet livery editor could work, however would work best if you could change the type of paint only e.g. Matte, gloss and choose different sections to change to your liking. IMO this should be the furthest helmet customisation should go.