Looks fine to me. I've been riding Monsters for 27 years, and have put 300K miles on them, and I'm fine if they change the frame design. Once upon a time, all bike frames were welded steel tubes; then in the '80's the Japanese manufacturers all went to extruded aluminum beams for their high performance bikes, because those were better. Ducati couldn't afford the extrusion machines, so they developed a method of triangulating welded steel tubes, combined with a stressed engine design, that was as good at the time, and made that one of their trademark designs.
To me, the thing that makes Ducati special, the reason I ride them, is that I prefer twins over fours, and Ducati was the only real sporting machine that was a 2-cyl design. The desmos are cool, but functionally, they are not a big advantage ; they mainly allow for more aggressive cam timing than valve spring designs.
Other than those 3 things, and Italian design flair, Ducatis aren't much different from other bikes.
So yeah, I'd be fine with an aluminum-framed Monster, with valve springs, and whatever else they wanted to do, as long as it was (a) a naked standard bike, in order to still be a Monster, and (b) a 2-cyl engine, in order to keep what makes Ducati good for what I like. And if they go to a V-4 at some point, I won't claim it isn't a Monster anymore, either. I just won't buy one and would get some other twin -- a KTM or Moto Guzzi or BMW or something.
PhilB