Yes, definitely agree on the spell casting. If I do cast something like finger of death, I want to feeling that I'm casting something incredibly powerful, not just have a pop, flash and death, I wanna invest in my super powerful abjuration, and be punished a bit for attempting it. Interrupting also should be a part of it, if theres a long incarnation, theres a risk of being interrupted if spotted and conversely interrupting other casters.
