They'll keep the 'twin' brand image for now. I just hope for a V4 homologation special. They've never released a one-off bike for that purpose, but they COULD make it work because everyone would want one. Use a similar monocoque design so they don't need to re-work the chassis geometry and flex characteristics of the parts they already know work. The only catch is a price cap on homologation specials, that's an idea being toasted around over the last few years. Making another Desmosedici would only ruin the value of the older bikes, so they probably won't do that.
I know they're working on an electric bike. I have a friend in the electronics business in Italy and he told me Ducati has been futzing around with a hybrid design. A much smaller engine with an electric boost. This way, the bike can still be a twin, still make the sounds of a twin, but be a lot more efficient. Who knows if it will ever release, but it's for sure an interesting concept and of course my friend doesn't know what platform they've been using. I'll say this much, the Panigale's monocoque design does offer a huge advantage for electric powered machines. Just hang the battery and motor from the subframe, it may work pretty well.
Here's hoping they don't change anything. Twins are a dying breed and it's nice to know someone still makes a good one.