Why are you so against a Livery editor?
Wouldn't you like to be able to create your own decals and personalise your cars to suit your style rather than just use a paint chip and have it looking just bland?
I know I would welcome a livery editor on GT5, So who cares if it hadn't ever been implemented before in a GT title, There are a few features that are in GT5 that hadn't been implemented in a GT game previously, Such as the paint chips, Gifting, B Spec Remote Racing and so on.
Just because this would be a feature you wouldn't like to see personally, It doesn't mean that the entire world who wants a livery editor is childish.
They ( like me ) Just want to be able to personalise their cars more, what's childish about that?
If PD actually did include a livery editor in a future update and someone wants Bugs bunny plastered all over their Zonda or Enzo.. hell.. Let em, It won't harm you or your online games, And it sure as hell won't give them a distinct driving advantage over you.
They just want their cars to look smart as they fly across the finish line in their choice of livery.