I just hope this time Nintendo will have enough system sellers in quality and quantity for the years 4, 5,... of the lifecycle of the Nintendo Switch. It's because since the polygon era, that's the time when Nintendo starts to struggle with their home consoles/start to entirely focus on their new console in the making. After 2019 Nintendo will have all their big sellers on the market (if mainline Pokémon really comes out this year). What kind of big sellers will they have from 2020 onward? A real new 2D Mario? a 2D Zelda? Mario Kart 9? Sequels to Zelda BotW and Super Mario Odyssey? Splatoon 3? Pokémon spin-offs? entirely new IP's? Or can they pull of a casual hit like Wii Sports/Wii Fit/Wii Play/Brain Age or Nintendogs/cats? From recent Financial Reports we also know that they haven't give up on Quality of Life (QoL). Maybe they pull off something in connection with the Nintendo Switch.
Late-gen is usually when Nintendo brings out their new-IP and stuff from their younger developers. Games like Smash Bros on the N64 and Splatoon and Mario Maker on the Wii U, etc were all fairly late-gen titles and turned out to be surprise hits. I am hoping that the Switch gets some of this treatment as well.
But a very good December for Nintendo. Obviously a mainline Pokemon on the Switch is going to be gangbusters when it comes out and so I doubt this was the Switch's peak year. It will be interesting to see in 2020 what Nintendo is going to do to keep the momentum going. I definitely expect a new Mario Maker to be in the pipeline.