I go for the mages first with the human in the hunt, because there is no second point of entrance. This is how you would kill them in most rooms of the dungeon.
But what if you cannot sneak to them?
I just killed 5 archers with one damage and one leap scroll with the human in my bare hand campaign (so with 1,1,1 equip). With 5 mages you would just have me seen running away. The difference is, that you can often do an avoiding+killing bull-rush step to get rid of them one by one.
You agreed that you attack them first with dwarf (and probably this is intended gameplay: Always kill the mages first - so they HAVE to be dangerous).
This might be fine. All I said is that there should be a reasonable strategy that does not need a health point per mage. If you have 3-5 mages I typically try to “let them move”. But if this is not possible and there is no second entrance I skip the room.
So this might be also a fine “strategy”. Even in hunt it is possible to leap to the exit. In the dragon lair “massive scroll consumption” is a solution (or dwarf).
Of course we can say all this is fine and not “too difficult”.
But if you get 4 dragon mages and 2 dragons in tournament in a room with the elf, cannot leap the mages (because 3 are at a single wall) and the center field is blocked, you may see that your options are very limited and this room will be costly.
We can say “bad luck”. This is also fine. All I want to point out is, that the reason for all these “avoidance strategies” (kill them first, use entrances, keep them moving, skip room) is that they are “difficult” in some sense and this difficulty grows non-linear with the number of mages in the room. Especially 4+ mages is pretty tough. If they are meant to be “dangerous” and to be “attacked first” then they could appear in lesser numbers in one room. OR we have skills to handle it. And this is the point here. Human has cleave, dwarf has worms and elf had counter against fireballs.
Another rule option as way out could be:
Mages cannot cast when this cast is already performed in the room. This way we don’t suffer a “rain of fireballs”, “confusing amount of summenings” or “titanic enemies in one turn”.