I remember that the first fragment took me 4 tries. Then, the second one took me almost 30 keys (it was horrible!). But then I got the third one probably after 8 tries, crafting the first weapon. Got the the fourth on the next day, so it was in the 8 keys frame. Then, I got extra 4 fragments in a single day of 20 runs and 20 keys. I don't remember well, but it took me probably 15 runs to get the final one.
With such low drop rate, its VERY inconsistent. At least, after I got the Nightlocke scythe, running the dungeons became even faster.
It would probably be better (in my opinion)if the dungeons are made more challenging or maybe longer(if it is already challenging for, as you said level 12 or 13 players) BUT with a much higher drop rate or even guaranteed drop rate. Longer as in more rooms and more challenging as in certain criterion such as completing the dungeon under a certain amount of time or players have only a limited number of respawns. I think this makes players feel more satisfied as it is obtained through circumstances like these rather than just RNGs. If based on RNGs(like now)one may obtain it in the first try or wouldn't even get a drop after a dozen of tries.
I'm all for that! Unfortunately, there's some time limitations. If the dungeons are too long, It deviates from the idea of being able to do quick dungeons runs on your phone at any time.
But I really like the idea of obtaining certain items by completing concrete actions or fulfilling a specific chain of objectives, rather than RNG for everything It would give players a sense of progression, in a way that they feel they actions actually count to get the items, but we could then have bonus RNG stuff along the way as to give extra flavour and surprise.
One example of this would be adding random special rare drops to every single monster, be it in the world or dungeons. These would not be farmable in specific monsters, but instead , every creature would share this 'pool' of items. Bosses could have their own 'pool' of items they could drop.
This would give some extra excitement when running dungeons, never knowing if or when you are going to get something special. Running previously completed dungeons could still be worth doing, even while helping friends with content you don't need anymore.
Who knows what you could get? Getting all those items could be very difficult, but you would be playing the game anywhere you want, rather than the SAME dungeon again and again and again.
(Maybe this would be hard to do because of the amount of items they would need to create, but it would be super cool.)