There are already hotkeys to switch between skills in DD, though unless you do some manual file editing it is limited to the function keys.
An extra column in the stat window, or tooltip description, would make it easier to compare new stuff with your current equipment.
If Larian wants to leave the ending of the game at least somewhat open, they can not really allow playing after defeating the Demon of Lies. I suppose they could let Zandalor teleport you back and forth between the wastelands and Council Hall, but there would at the very least need to be dialog changes with many NPCs to reflect the increase in Black Ring activity (I don't recall if anything was mentioned specifically about how much time had past, or what had happened to areas in Rivellon that you had access to).
You can hold the shift key down to move the screen focus away from your character. DD is a 2D game, so it is not possible to change the camera angle.