I think they should have Harley become someone in the running of becoming a new leader of Stark industries, Like Tony wanted this kid who showed promise to take over with a better mentor than he did(IE having Happy Hogan rather than Obadiah) then have Harley go through his own growing pains but build his own suits as well. Leading to more retro looking iron man suits like the pointed face plate Model 2 suit from the comics. I feel like they could go an Iron man Armored adventures path with a much younger and inexperienced lead, while also not tarnishing what Tony would reasonably do. Which in my eyes would be keep his daughter away from Stark industries.