In terms of the game mechanics, I think Dungeon Quest has already done an exceptional job, the game has one of if not the best and most complex ARPG system in the mobile game market, the next move in my opinion is to focus on polishing the game and adding more contents instead of mechanics, improve on aspects where Dungeon Quest falls short on.
Things like new mobs with interesting abilities, more variety of environment, floors and levels are what Dungeon Quest really needs in future updates, I mean we've been slaughtering the same mobs over hundreds of repeating floors since the game first came out, it's time for something new, maybe an extra act? Or even a real map like in Diablo and Path of exile, not just repeating floors that vary only in colours, just something to think about.
The game can also use some detail improvements.
For example I noticed some weapon swings don't have trails, such as whirlwind.
And weapon strikes overall simply don't feel very impactful(except hammer), I think it has something to do with weak sound effects, because there is only one sound effect that loops with exact same interval regardless of your attack speed, number of enemies hit and all that..
General improvements that needed to be done such as sorting in stash. I don't get it why is this even missing, why bags can be sorted but not stashes? Doesn't make any sense. Fixing little things like these can really go a long way in terms of improving the overall experience.
I hope the suggestions are helpful!