Can you give an example of the type of feature you were required to remove due to the approval process?

Yes of course. We had to remove the integration with the notification API and also remove the facilities which allow us to install the CA certificate smoothly into your device. The second was flagged as breaking a clause which states that all applications should be self-contained. Which in our opinion is understandable concern although the feature would have saved a lot of people an extra step to get the CA and other certificates in the correct place in order to ensure smooth communication.

What blocked you guys (if you can say)?

If I can give any tips, whenever I'm questioning if a feature is going to get called out when I submit an app, I always fill that "info for reviewer" section with tons of stuff. Explanations, links to docs & legal to show that I'm not doing anything against the law/rules.