My theme will be getting as much grasp of the big plot as possible, but at the same time obstaining from the tadpole usage. Detecting every thought, speaking with every dead, perceiving, investigating, persuading for knowledge etc. Would probably require a solid number in arcana and insight. I am literally aiming for beating the puppeteers at their own game, while not giving them any excessive advantage against me.
The second thing I am aiming for is giving my companions a test of trust. I'll be merciless to anyone who betrays me - "cull the weak" - you may call it. I am looking forward to putting down Shadowheart first after she spoils her "gith problems", probably stake Astarion during THAT night. Haven't decided on Gale and Wyll. The first one seems to be a huge impediment with his explosive problem, but just killing him would not suffice. Might have to carry him around or leave him. Wyll has some short temper, but I could keep him for his skills (not the rapier skills unfortunately...). I would probably follow with the Halsin path and join with him, he seems pretty competent. The Absolute path can easily force me to use the tadpole at one point, which I don't want.