SureAI

I beat the main quest but I don't know how much else there is to do -- did I really get that set of armor just for the last guy? Or is there more to do?

Also, I can only use spell level 4, but I know there are supposed to be 7 levels.
I'm not sure if the spell levels come with casting experience or how that works, but I seemed to be able to use new spell levels at certain level ups (although I focused on Marksmanship, so maybe it was just my skill set). Since I'm only 4/7, it seems like there is more to do?

Do people generally just take it as a sandbox game and go explore on their own and level up for other spells, or am I just behind on levels for beating the man quest, or what?

Sorry, it just seemed like it cut off kinda short

Thanks

Your character must have level >= 7k in order to be able to cast level k spells. Or maybe it was 7k+1.

Did I just complete the game early, then? Or is it uncommon to actually get to spell level 7?

OK, I was a bit wrong. It's >= 7(k-1). So you need level 42 to get spell level 7. That's something not everybody achieves