What extensive teasing? They have new model as a tease. Its mentioned on the map for the first time ever. But otherwise nothing else has changed since the intital announcements. The information boards inform guests that a coaster and hotel are being built but there's no new info and more than anything they are just replacements of the previous signage in the park which are now gone due to the new Wuze facades.I honestly don't understand why they're not straight forward with if this is supposed to open this year or 2020. The extensive teasing suggests sooner than one'd think from how the construction site looks.
Otherwise its still radio silence from the park on the project - especially compared to the amount of videos and blog posts released during Klugheim's build (from August 2015 to opening in June 2016).
At the end of the day if they announced "Autumn 2019" but then as with Chiapas they're struck down with prototype technical issues and it ends up being 2020 people will be more pissed off than if they announce it when they are completely certain its all ready to go.
Also announcing a late 2019 or even a 2020 opening would potentially deter some people from visiting or booking a stay this summer so I find it understandable that they keep quiet until closer to the time.
And to be fair when the park say "It will open when its finished"; they are technically being very straight forward and honest with us.