The bosses get more interesting from a mechanic point of view starting from Bonemass. They are ridiculously easy prior to that, assuming you don't cheese the bosses in which case they are all easy and boring.

The armor grind isn't necessary and can save you quite a bit of farming time. If you think about it, armor is just insurance against making mistakes. A lot of players prefer to run light armor for the mobility and focus on not getting hit. I'd rather do that as mining makes me fall asleep.