I am with the Affinity software since it got out - have it for Mac and iPad.
I am very exited to see the Publisher app to come out soon too but have some stomach pain here.
The main angle I see this is coming from Macromedia Freehand that unlike Adobe Illustrator / Indesign
offered layout, masterpage, text tools (Indesign) and Illustration tools (Illustrator) in one application with
another major advantage: different paper formats.
So in stead of having different InDesign files you could have all in one design document.
I see Affinity stepping into the same highly frustrating and annoying limitations Adobe forces onto users.
Freehand got killed and typography and text frame tools where separated so nicely that you need to buy
both Adobe apps.
I really hope that in the long run chaining text frames, master pages, etc will be accessible for Designer too
and not only be limited to Publisher.