Hi Chris, welcome back
The “changeover” announcement for K3 is here, note that this was an extraordinary situation and certainly not something we wanted to inflict on you all. But we had to start the app almost from scratch and we’re a tiny team of 4 (not even full-time) people, so yeah, some functionality is still not there, but we’re working hard to bring K3 up to speed. You can find the planned features here
In the meantime if you can’t live without a specific feature, we won’t stop you from using the older versions (in parallel). Also we’re really super active here on the forum and you can tell us (as you’re doing right now) which things are important and missing.
Offline maps in Kurviger 3 are handle in a much simpler way than before, as a Tourer+ subscriber you’ll find them in the sidebar. Also the path along your current route is downloaded automatically in the background when you start the navigation, no need to download country-specific maps anymore
During navigation, click on the destination / waypoint data to switch between duration and arrival time. This is clunky and hidden, we know, we are currently actively investigating how to improve this!
You’re talking about the planning view? There are buttons at the top-right to make the data window larger or smaller 
When you click “start navigation” and your current location is not near the start, this popup will automatically show up, and you can decide how to handle your desired process
Yeah we are aware of that and it’s super tricky, since we now have quite the international audience, there are posts in German, French, Dutch and English. For now we simply have to work with Google Translate as we need to pool our resources and don’t have a support team which could take care of dedicated help sites. This is a place for the community to meet and help each other out when the developers currently just don’t have the time, we need to keep this in one place. See also this. As for all other things I have written here: do let us know if you can think of a better solution
I really hope I was able to improve your experience here. We truly did our best to communicate the changes on Kurviger in all available channels. We posted to Facebook, Instagram, our blog, the forum here, we have a Changelog, you get emails from forum posts, etc.
As I said it was a rough situation but we did the best we could with it: you now have one account for web and app, the cloud is synced automatically, the app is more lightweight to use, it already has lots of features the old app didn’t even have and there’s so much more to come