The M8 isn't going to appeal to millennials anymore than an Evo or TC. Add a suspension that can be adjusted from the handlebars, variable ride settings (rain, cruise, dynamic), reverse on tourers, Apple Car Play, water cooling (yes, it's time to head that way), etc.
Sounds like a Honda or BMW.
You're right, some millennials wouldn't go for a motorcycle even if it was self driving operated by an app on a smart phone. So we as veteran riders must focus our attention on those who love the new found freedom that comes with motorcycling, and that market is women and minorities. If we are to keep this sport alive, we can no longer afford to view new comers as LBGT, Latinos, Blacks, Asians, Non-Christians, Conservatives, or Liberals. Regardless of the fact that we all ride "Top Of The Line CVOs", we must welcome all motorcycle brands.
So "ask not what can the moco do to keep motorcycling alive, but rather what can I do for motorcycling".
Speaking for myself, I love to tour with my friends. This year we went to Yosemite National Park. Next year it's Sedona, Prescott, The Grand Canyon and The Petrified Forest. If you can make it, great. If you can bring friends even better. Check out next years ride in the EVENTS section of the forum.
And finally,...some millennials do ride. You see them now and again, their choice of bike is a 1970s era Japanese bike like a 360, or 750 that's been chopped up with a "naked gunfighter" look. You see them ridden by young men with their hair in bun, a goatee, RayBan Wayferers, and a shoulder bag. The women wear shredded jeans, and leather overcoats with half helmets and goggles. I know you've seen them and wondered about them,...their the future of keeping this alive.