I do follow Michael since his Bennetton days, and it never fails to be pointed out by his detractors, that not a single team, including Ferrari, will build a car around you, unless they understand benefits of choosing that direction. Schumacher had shown convincing talent, he has demonstrated speed, and Ferrari would have been pretty dimwitted to kill it, rather than explore it. Herbert, as others, had every chance to destroy Schumacher in real or potential terms on the track, and then he could walk into JT's office and demand a design change!
History suggest that he has never reached a level that he could actully convert this thought about it into some realistic opportunity.
Exactly. I think most of his teammates preferred an understeering car while he was the opposit and his way was by and large way faster. So his input carried more weight against more experienced scrubs like Brundle and Herbert.