I agree, Disney can produce thrilling coasters if they want to. Unfortunately, the 90s was a different era, but who knows, maybe with the success of Velocicoaster and Stardust Racers, Disney might want to compete again in that market. But I just don't see current Disney building a coaster with inversions.
It depends on what the audience is calling for. Personally I want more dark rides but lately DIsney has been coaster heavy, if not thrilling, coaster heavy due to competition's success.
I prefer one or two great that have a thrill with a balance of Dark Rides and Shows for the rest. But that is not the norm as audiences have gotten braver and coaster types becoming more accessible.