A simple suggestion though I am ignorant as to the difficulty of its implementation; often times when using the Spellthief ability it's very difficult to tell what was actually stolen. In the thick of combat, especially in a close fight, it's optimal to know what buffs I currently have/need and so it would be a great quality of life buff for it to have a message in the combat log or something stating what buffs have been stolen.
100% agree. It'd be great if there is a combat log of which spells are stolen when the Spellthief ability is used.