"...If you asked any executive they'd tell you they're making really risky decisions all the time. So how would you articulate the difference between the heavy risks they _feel_ like they're making and these Walt Disney-esque big-payoff types of risks?"My biased response is, "It's the kind of risk that inspires the creatives in your company." Your creatives are the medium between an idea and its audience, and if it doesn't inspire them, it's unlikely to make a lasting, positive impression in games.
An idea executed with inspired creatives is no guarantee, but is the only concrete minimum requirement I would offer when influential vision is the goal. Anonymously poll your most valued creatives. The answer may not surprise you, but it can help.