Shackles is great in the early and midgame while the game is still not super trivial. I dont plan a build for 15+ i plan it for 1-15 basically because after that you are an immortal god anyway. Executioner will not give u +4 AP if u kill 2 enemies at once. It will only give you 2 until next turn regardless how many you kill.
I have started another solo campaign with Sebille with all this in mind. Finesse was a hell of a lot easier in the early game Compared to INT. Id recommend starting out with a rogue/ranger build and respec into this on the boat. Struggling to get to lvl 4