I think if the dungeon layout also changed, or it was at least more visually interesting, there would be a compelling reason to replay the same dungeon over and over until you got the right loot, but because the layout is static, it's jut not that compelling. Also, and I'm not sure why this is, but I learned that the loot changes and that better loot makes the boss fight easier, but once I got to the next level, that knowledge escaped me again when I ran headfirst into an enemy that one-shotted me. I'm not sure if there's any way to telegraph to the player that you need the loot before you take on any fights, but it really didn't stick in my head when I played it. I actually think you have a pretty promising base for a game, that could be tweaked a bit to be pretty compelling.