The BG3 problem: four protagonists competing for the spotlight will not make a good cast. Choosing to play as an Origin character will not do anything to fix that. A Tav is just a mechanical variation to that, shallow of content in comparison.
The dynamic of a PC protagonist with companions for supporting cast has worked great for all party based RPG's before, but of course Larian had to reinvent the wheel. Thinking outside the box is great, but you need to see what actually works and what doesn't.
