Same boat I'm in. Current plan is to skip Horizon for now, play Zelda on Switch, then get Mass Effect and then when done with that hopefully Horizon should be getting some sales.
But at the same time, I would have no shortage of games to play this year on PS4 Pro and PC, thus it probably makes more sense to wait and see on Switch and how it's selling etc. But like you, I like new things, and I like supporting Nintnedo.
So I'm torn. I just found out the review embargo for Horizon lifts on the 20th, so I'll wait until then and read a bunch of reviews. If I get more hyped for that than Zelda, I'll cancel my Switch preorder. If not, I'll keep it and stick to the above plan.