Thank you so much for this detailed feedback!
We're actually reworking the mage entirely, partially for systems reasons and partially because yes, she's an AoE powerhouse right now that trivializes every encounter. The new systems will be in the October demo, we hope you want to check it out!
Agreed on enemy variety - We likely wont have many new enemies for the next demo, but we've been plugging away on systems to make making enemies easier, so after that we'll start bringing some meaningful new challenges :D