If HD asked me I would have told them to take the 750 street engine, outsource the design of a modern, midsized, performance oriented (handling, suspension & reliability, obviously not HP) adventure bike priced competitively, namely without a "brand premium" worked in. At the same time I'd offer a down market alternative with less sophisticated suspension and a lower seat height. The design should have no HD styling cues (such as the tank shape on the adventure behemoth), a unique or resurrected HD logo, name brand suspension, brake and any other parts possible, and chain drive. It should also be assembled EXCLUSIVELY in the USA , but be emissions compliant in Europe.
Ramp up the appropriate marketing machines, including test rides on appropriate roads or at events, and incentivize the crap out of it at the dealer level, to the point that they can make good money selling, servicing and accessorizing them. The dealers who choose to poo-poo the bike and remain focused on their traditional customers can do so. The client will figure out where they're welcome.
If it works or shows promise after a couple years, use the platform or process to bring out other models.
If it doesn't work, then just accept that your share of the overall market will decline gradually and focus on build and customer-experience quality and organizational profitability.