I am still in testing mode on PoTD but my impression so far is that a stealth focus is still viable but you will need at least 12 stealth plus a speed boost to get by the most critical areas using items, food and/or rest bonuses.
My main concerns are that it is an extreme glass cannon build when min/maxed like this (18-3-18-3-18-18) - the Con penalty is -35% and Acc penalty is -7. The aim of the build is crit damage and AoE/DoT as well as conditions but you need to hit to apply them and you miss a lot with that penalty (at least in the early/mid game).
My current attribute spread is 18-3-16-8-15-18 which corrects most of the Acc deficiency at the cost of a little AoE/Duration and action speed. Still feels very fragile and I might want to sacrifice a point or two of Might damage for a bit more Con and survivability.
I love the concept of a sneaky rogue that bypasses all unnecessary fights and still prevails but you do have to fight sometimes and summons can only do so much to help - you still have to be able to do enough damage to finish them off and be able to survive the inevitable hits. That said, I am really enjoying the character and this approach to the game.