I can't see another Zelda getting released before BotW 2. We had a main Zelda game in 2017, two ports/remakes/spinoffs: one in 2018 and one in 2019. So we will probably have BotW 2 this holiday or early next year. People expecting WW/TP HD ports will have to wait. I don't think Nintendo wants to release more than 2 ports/remakes/spinoffs between main games. There's more than enough already.
Edit: Actually, I forgot about Cadence of Hyrule, so we already had 3 games after BotW. (I was counting Hyrule Warriors port and Links Awakening remake)