Call me crazy, but I believe Switch is indeed them trying to be more mulitplatform-friendly, far more than in the past, as well as developer friendly. Between the ease of development and the engine and tools the platform supports, this is by far the best development environment for third parties; it's certainly a far better foundation where to start from compared to the past generations. We'll have to see how much this is going to help to pursue more multiplatform releases, but it's clear how this is a solid start on that front.
Certainly, what remains to be seen if, besides the solid foundation, there is something else, i.e. Nintendo incentivating multiplatform releases even more. Right now, we're seeing a small number of upcoming multiplatform releases and late ports, but it's not unreasonable to think the next few months can see more announcements on this front. However, I strongly believe next year is when we'll seriously see how much Nintendo obtained to do on this front: this year we'll still see games which development started when Switch wasn't even considered in the picture / dev-kits were more limited to specific branches of the same company / are not coming because they want to see how things go first. Digimon CS probably falls in one of this cathegories.
Since you've mentioned Musou Stars: I'll be honest here, your idea is not - that - awful. It's actually what I believed could've been the launch Musou for the system, including the Zelda exclusive content in order to attract more potential customers. But I suppose both Koei Tecmo and SE believed that a collection of both DQH + new content would've been a better and, above all, less risky way of getting the spotlight as one of the biggest launch games while trying to start to establish a Musou fanbase on the platform.