Ok. Let's assume that voiced protagonists will always be present from now on.
What is a solution to make it easier to roleplay a character fluently on the first go?
Sorry for the lack of response; was in meetings and missed this.
I've been down this rabbit hole. Conceptualizing solutions, discussing alternatives, identifying weak links in the chain... heck, I've even done with some of the Devs like Allan and David over the years.
Long story short: given enough time, resources and commitment, anything is possible. But cinematics are already becoming more resource intensive under Frostbite - as evidenced by the complete removal of any cinematic approach on side quests. Those shiny graphics and "character creator that's able to make daenerys targaryen" means it's also a bigger sink to try new things, like player control of body language or facial animations.
If you really want a solution? Okay - take out gender and racial choice. Make the default be a dwarven female for all I care, but eliminate the variables. You can then do a dump truck worth of things you couldn't do before (or coukdnt so easily). Heck, even make the default weapon set in stone - a sword, for instance. Or a bow. Then people can have scabbards or quivers or whatever their little role playing hearts desire.
Other solution? Keep all of the character creator choice, but lock down the personality. Be an apathetic anti-hero haunted by your past (cough, Geralt, cough) or be a bad ass warrior who wants to find her lost tribe. Or whatever. Then you don't have to worry about what your character would or wouldn't say - you've got a set background and personality, so there's nothing to worry about.
Outside of those two things, the only solutions are either so high cost and high tech that they border on the ridiculous or so low tech (like simplified isometric graphics and a silent main character) that they lose their "flash" that most players today need in their games. Those are my solutions.