I think franchises that were previously either mostly restricted to a portable or stationary console appearing on a single unified system is already demonstrating the effect of focusing development on a single dedicated gaming platform. In addition, Nintendo prioritizes having one release of some their franchises on each platform they release, these resources can now go into making a single release for some of these franchises which frees up the developer to do other things.
Although, I would argue that even after 3DS (assuming Nintendo does not make a completely different platform from Switch to follow 3DS), Nintendo's dev teams are not truly unified. This is because Nintendo wants to expand its online efforts, and this not only involves external partners like DeNA but also first party studios like Nintendo EPD and Intelligent Systems. Just look at Super Mario Run, Animal Crossing Pocket Camp, Fire Emblem Heroes, and the upcoming Mario Kart Grand Tour; all of these are examples of games developed using first-party resources.







