It would be nice if small items could display their stats, in abbreviated form, like their large counterparts do. E.g., the current damage dealt by BURNDAYRAZ or the current charges on a Fire Heart. Just the number value would be enough, really. It's something of a niche case (except for Wizards and Tinkers) but having to mouse over the item just to see whether it's charged up yet is a bit tedious.
This is an even more niche case, but I'd be quite happy if there were some indication of which monsters have already been affected by the Wicked Guitar. Maybe just add a "Wicked" status to their description. It's sometimes hard to figure out when and how often to use it when I can't remember if it's already targeted a monster that I don't want to make too strong.
It would be nice if the gold rewards for hard and vicious dungeons were increased, even a little bit. Particularly in the case of Namtar and the Library, which have neither trophies nor quest rewards. Maybe have a difficulty multiplier for gold rewards from new badges and class completions?
I think Berserkers should get their full +40% (+20 and +20) against level 10 monsters even when they're at level 10. They're kind of underpowered now as it is, and in vicious dungeons where you basically can't avoid hitting level 10 it's a significant weakness. Honestly, you could probably change their extra +20 to work against all same-level monsters (and still higher-level monsters, obviously) and I don't think it would be too overpowering. Might even get some more use out of the Balanced Dagger that way.
Mystera's Flames boon would be a lot more attractive if it spawned an extra BURNDAYRAZ glyph (zero conversion value, obviously). Particularly for those cases where you've either already converted it or haven't found it yet. The attack penalty is steep enough that it could use a little something extra, and it's also a little odd for Mystera to be one of the only deities that doesn't give out a free glyph.