The "exploited" numbers gave as standards by OP seem to have derailed the debate a little.
Even without a troll spec, ATG + Decap is too much. When you hit 6K decap it's almost always a kill blow and we all know they are buffed. It's like 5K TTS complaints. They occured when you had, at best, 3.500hp left. And a 3.5k crit is, depending on circumstances and frequence, acceptable. The probleme with Decap + ATG isn't that it can one shot a full health BS once every full moon, it's that on a daily basis you have a steady, reliable, unmissable 4 to 6K burst damage without missing much of any good feat.