Cool game, I like the concept. It's a bit like MMO healer gameplay, without the MMO part. I see in another comment you mention hotkey gameplay being challenging to do right. I would look into Monks in Guild Wars 1, specifically the protective spells. It is without a doubt the best designed hotkey gameplay I have ever seen, and it's not even close. Prot monks in GW1 PvP was some of the deepest and most interesting stuff, I'm getting nostalgic talking about it. It encouraged an extremely proactive gameplay style that really rewarded the player for having deep knowledge of how the game worked, what the enemy team was doing, what your own team was doing, etc... It's such a deep well, and it's barely been tapped. It would be a great resource to draw from here.
I also see similar complaints as to what I had earlier in Necrovale gameplay (its boring, just fighting the same skelly over and over). I think the problem more turned out to be one of higher level game structure, not repetition. You have done a lot of work to guide the player to their next objective, but where things really started to click together for me is when I gave them a bigger picture. In my case, it was just a map that came up showing all runs they would be doing, and where the bosses were. Nothing more than Mario did over 30 years ago. It's a minor thing, but it gives the players a sense that there is a certain journey they will be undertaking.
The idea that there is a long way to go needs to be embedded in the back of the players mind. If they have that, they can endure a lot of repetition and tedium and grinding and imbalance and whatever other problems inevitably come up. Because ultimately, the player wants to be spending time in the game world. Its important as the designer to message to the player that you want them there, that you are on the same wavelength.
Keep it up.