I kind of wish there were some bonuses. As long as there was balance, and each article came with disadvantages too, you wouldn't see too much of everyone picking the same thing. For instance, "The Shield" look provides extra defense, but slows movement and limits agility some. So maybe someone playing a medium on the front lines would be interested in parts of that set up, but it wouldn't necessarily be the best for everyone else. What you would pick would be dependent on play style, not necessarily your class or build, though that would probably also factor in.
customisation with stats=no customisation
if it has any effect on how your character is used, it's part of your "build". not part of your customisation.
just like the only part of customisation on guns is
1) scopes
2) skins
i'll take customisation over stats all the time. the abilities/classes are good enough to work with in my opinion