Fire/ is one of my favorite primaries. And /Time offers so much to it. But the End is really the problem. You might want to consider the Primal Forces Epic Pool. Power Boost+Farsight is an amazing defense mechanism and you'll be tanky enough to be running into those fights head first. As long as you don't build a proc build, Ageless will save you from all your End problems. Stick with it through those tough levels and get yourself some End Redux for your toggles and +End procs (all 3 in health and the 1 in Stamina) and it becomes a slight bit better.
Personally, I got XP boosters and ran through lower levels on mine. You'll be really happy with it in the end, I am sure.
Oh and DO NOT FORGET the Knockback to Knockdown proc in Bonfire. Yes Fire Cages has that effect, but opening with Bonfire is a lot nicer than opening with Cages.