The problem I see with it (besides the aforementioned HUGE FUCKING TARGET ON YOUR HEAD IF YOU BUY IT) is that Trailblazer synergizes with more junglers' clears better.
There was a game where I kinda wanted to try Poacher. The enemy team's top had to be babysat for a good length of time, and no one on their team was buying wards.
However, I was Rammus.
Rammus, and other tanky junglers, cannot kill just the large monster in a camp, not without difficulty. By the nature of their kits, the smaller monsters die to AoE splash damage most of time. Trailblazer is the better buy in that situation. TrailB scales into the late game better too. Unless you -KNOW- the enemy team is gonna fall apart, which sounds better?
A faster overall clear, possibly large heal/mana refresh, and sets Smite's cooldown to a base 45 seconds.
Or
A Smite that only goes on that 30 second cooldown if you take farm in the enemy's jungle, along with a good MS buff for 2 seconds if you do so.