I'll only give a few spoiler-free answers.
There's more stuff to do in the hinterlands than what you described. There's also more things you can discover, even if you cannot act on them just yet.
There is not enough time to do them all. You have to choose your priorities.
We might add a few more little things to see in the Hinterlands in future versions. We had some ideas we couldn't put in because of time constraints. But that definitely won't come in with a time extension, as that section of the game was designed and balanced with that time frame in mind.