I do think we'll see series like Wave Race return, but I think that has more to do with Nintendo's online subscription than anything else. Nintendo can't rely on the mainstream FIFA/CoD/Battlefield/Overwatch/Destiny crowds for online subscription payments on Switch, so they need to bring out their own online games to keep subscriptions going. Games like Wave Race, 1080, F Zero and the rumoured Star Fox Grand Prix fit with that need.
The implication they're trying to get gamers who left the fold is interesting, but that could equally end up being a play on nostalgia more than trying new, 'gritty' IP. Look at Pokemon - the rumoured return to generation one/Kanto will see Pokemon return to its most recognisable, mainstream incarnation, for example. I think you're right that Nintendo will use their streamlined development capabilities and one-system focus to try and provide a more versatile software line-up than before, but I don't necessarily see that coming in the form of mainstream, 'gritty' IP. Time will tell.







