I'll touch on things that might be appealing, to go with this. Pots are a mainstay for mabi. However, rather than throw a bunch of different pots in the chests, i'd add a full stack of red or yellow herbs, or 5-7 blue herbs, as an included drop in most rewards. Give incentive to not just running the dungeon, but some minor drops for training pot making, and the result you get will be desirable which is going to help encourage that.
Similar could be done for other skills. Make specific dungeons themed somewhat towards other production skills, add some ore or ingots as rewards to barri drops, scaling the tier with the difficulty you run. Now obviously these aren't meant to replace rewards, but to go hand in hand with them, or possibly not drop at all sometimes.
Moving on, weapons and armor. At the start, these are what you need. I'd suggest scattering more sought after gear, as rewards. Don't know how feasible this is, but obviously could have various potential stat changes, with the harder difficulties being more likely for multiple stats to be good. Also, different colors on the gear. Because nothing grabs players' attention better than that rare red and black color, and even better when they realize it can have different stats and they can farm for the best stats to go with the color.
LLB is a common weapon, as a giant it'd be nice to see Claymore and Battlehammers added somewhere, with better than NPC value. I don't remember what humans dual wield, or what giants think need dual wielded, but those could be added.
Part of the issue with dungeons though, is that they're low level content for the most part. Thus, adding too awful much to them will feel unbalanced. But at the same time, if you don't add something worthwhile, they're just a waste of time for most people. Some production mats would help some, and i think some gear would, but the finer points of it would have to be smoothed out. If the GMs can add say mini-bosses to the dungeons as well, giving them unique drops, (unique as in they drop things you may not expect of that mob, not just rare items) it'd go a long way towards dungeon productivity as well. Of course then you're going to hit the issue of what's appropriate for the dungeon/difficulty, that won't be overwhelming to players there, or feel harder than the current boss.
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Discord: Tonkatunk#7079
https://github.com/Tonkatunk/Mabi-Pro-Lazyfae-Mods