Though it affects visibility
I’ve already played two days worth of Metal Gear Solid V: The Phantom Pain. It’s good stuff. Anyone attending gamescom in a couple weeks will be able to play it, too, in the first public hands-on. All well and good.
The Metal Gear Online Twitter did do a Q&A, recapped in the forum, most of which focused on customization. Some gear is class restricted, but you can change color and patterns of various body segment attire. Nothing is unlocked from single-player and nothing carried over from Metal Gear Solid 4. Outfits are also aesthetic choices, in that they don’t affect stats at all, though they will affect your visibility, which is worth considering.