Putting aside the fact that not needing armor doesn't equal having to wear high heels and skimpy clothing, I don't feel like this is something that's a characteristic specific to Miss Fortune.
If anything, the whole "Doesn't need armor cause she's ranged and won't be in melee range" is reflected a lot more in a champion like Tristana (Pushes enemies away, increases her own range, leaps away to escape, etc.), yet she wears leather armor, goggles, boots and gauntlets, which to me makes a hell of a lot more sense for a gunslinger archetype.
E: I don't mean to be trolling or anything and I suppose this is somewhat offtopic for this thread, but I do think this is an interesting subject to talk about.