I'm in a weird spot with Nintendo at the moment. Pokemon, Metroid and Fire Emblem were the core of my gaming interests for years... but all three of them have really slipped for me lately. I didn't enjoy Moon at all, for too many reasons to list right now. Fire Emblem's recent emphasis on marriage has come at the cost of interesting supports imo, and the characters seem much more one-note than they did pre-Awakening. I don't even need to explain the issues with Metroid.
I was also a huge fan of Smash Bros. and Mario Kart, but I think I'm past the point of being able to get much out of those kinds of games. Back during the school years I'd play them with friends weekly (if not daily at points), but that just doesn't happen anymore. Hell, I was the only one in my circle of friends that even owned a Wii U, so online was out of the question as well. Playing them solo or online against randoms isn't all that interesting.
Anyway, I do like most of their other franchises, although with these it was always much more of a case by case basis in terms of whether I enjoyed it or not.
Zelda - Many of the games are among my favourites of all time. The DS games were really average though. Twilight Princess & Skyward Sword didn't do much for me either.
Mario - Not a fan of the 2D games anymore. Super Mario 64, Galaxy and Galaxy 2 are ace though. Wasn't a fan of 3D World, but am excited for Odyssey.
Splatoon - Fantastic new franchise, looking forward to the sequel.
I'd be cautiously optimistic for any future Golden Sun, Star Fox, Advance Wars, Mother, F-Zero, Eternal Darkness or Kid Icarus game too. Honestly, the only 'big' Nintendo franchise that does nothing for me is Kirby, and I really don't need another 2D Donkey Kong game for a while. I think I'm just tired of 2D platformers in general.
In spite of all of that, I somehow already have a Switch! I had intended to wait for Odyssey if not later, but the launch day Zelda hype won me over. Can't say I regret it though - Breath of the Wild is some of the most fun I've had in a game in years.