Thom Bangalter recently suggested in another thread using this elite along with Concussion Shot as a viable use. While this may be the *best* use for the skill, it's still terrible. Why?
*Concussion Shot has a recharge of 5 seconds.
*Archer's Signet, in the current state, only works on your next 7 bow attacks.
*In order from you to gain any semblance of profit from this elite, you'd be using Concussion Shot as soon as it recharged.
*In order for you to use Concussion Shot with this skill, you most likely would not be using any other bow attacks, AT ALL.
*Why? 7*5=35 out of those 30 seconds on the duration of your elite. You only have 15 seconds downtime to "waste" bow attacks before you have to stick to Concussion Shot again.
*Using any other attack skills lowers the profit from your elite.
*As we all know, spamming an interrupt as soon as it recharges, that does no extra damage is bad. Not to mention spamming it 30 out of 45 seconds.
What could be done to turn this into a good skill? Well, you could tie it to Marksman, and make change the skill to be something more like this:
Archer's Signet: All your non-attack skills are disabled for 15...9 seconds. For 30 seconds, your next 1...15 bow attacks cost no Energy.
Or, better yet, you could change it to something I dreamed up when I was bored.

The most major change would be tying it to marksman, but in a different way. Check this out:
Archer's Signet: For 60...30 seconds, when you use a bow, your attacks deal an extra 30...1 damage, and have an additional 25...1 percent chance to critical.
How sweet would that be?

Tell me what you think, rangers.