I think the idea behind the Chalice dungeon is really neat and I can see the appeal if that's what you're looking for. I just think that it would be better in Dark Souls 1 or 2 where they could populate it with interesting stuff to find along the way. The few hours I've spent in it so far have not felt rewarding at all. None of the enemies or bosses felt all that interesting.
Also trying out new weapons is cool and all, but really any build is probably going to only be able to really take advantage of a handful of them. As a highly skill based character, there are only I think 4 weapons that are really optimal for me. So gotta restart a character to try out a new weapon.
I want to bet there are some unique weapons and findings, but people haven't found the right combinations for making them yet.
From what I understand, you can create dungeons with weapons. Why not try to create a dungeon with something rare?