It's not that complicated. It's 90 seconds so it always aligns with b4b, HE, quick reload and rapid fire. The principle of "when or when not to use wildfire" applies for every other cooldown (raging strikes, B4B and HE), while your oGCDs are on such a short cooldown you'd always them at least for one cycle unless you used it right before using wildfire.
What I would like is johnny's idea, at least that would make it applicable in something like PvP, trash mobs or add phases. Wildfire isn't hard to use, but it's only really good for single target bosses.
