I personally think it is a bit of a flaw of the game that only one armor set is used predominantly. But I know many people will disagree with that so whatever.
Heh, not nearly as many as you'd think...
Now that I look more closely I see the utility cooldowns are all 45 seconds with no cooldown reduction trait option. That's not exactly synergistic with trapper runes; those of ranger are much shorter.
The fact that all of their CDs are the same suggests they're just placeholders. They'll probably address the cooldowns last one they have an idea how powerful each trap actually is.