Having read your fanfiction I think you have plenty to add to how a custom character could be handled better (and our first meeting with Astarion for that matter)
Thanks! But fanfic is easy (relatively). I don't have to account for the amount of time and resources my non-existent developers have available. I don't have deadlines, salaries to pay or shareholders' expectations to satisfy. I don't have to worry about engine limitations and game mechanics and all the fans out there clamoring for a thousand conflicting things. All I have to do is steal the brilliant ideas of others, cut them to pieces and sew them into the warped fabric of my imagination while laughing maniacally.
I've made the occasional mod, and that is hard. Putting a whole game together... yikes.