I do think that, if Pokemon skips 2018 (and Metroid isn't coming out next year. No way), they are looking a little light on serious, "s-tier" franchises for 2018. I mean this year we had Zelda, Mario Kart, 3D Mario, Splatoon 2 and ARMS. While ARMS is never going to sell like Zelda or Mario, it's still being developed by the Mario Kart team and is a big, "AAA" Nintendo exclusive.
For 2018, in terms of those big "AAA" Nintendo exclusive games we've maybe got Animal Crossing (has anything even been announced for that yet?) and.... Fire Emblem? Yoshi and Kirby aren't what I would consider real "s-tier" franchises in the same vein as Pokemon or Zelda. Smash is still very much up in the air right now - we don't know what it is (Smash 4 redux? Smash 5?) and have heard absolutely bugger all in terms of real information from Nintendo. For all we know Smash 4 redux was just another rumour in the vein of Pokemon Stars being switch exclusive and coming out this year.
Pokemon would be an excellent grab for Nintendo in 2018 - if they have Animal Crossing, Pokemon, Smash, Yoshi, Kirby and Fire Emblem, along with whatever Platinum Games is cooking, that will be a decent spread of Nintendo exclusives. This is why I said earlier that Nintendo have got a vested interest in getting it made: it's arguably their biggest "exclusive" franchise in terms of selling power - the attach rates for a Pokemon RPG on Switch will be absolutely ridiculous, mark my words. Combine Pokemon with Animal Crossing, Fire Emblem and hopefully more 3rd party stuff and you've got a decent looking 2018.
Without Pokemon it's looking a little sparse AT THE MOMENT. Obviously there could be a hell of a lot more coming in 2018 which they haven't told us about yet.