I think you kinda exaggerate with your 10-30 hit combats...
first of all you don't mention the gold sink it brings with it (is this wrong?),
because a 10hit battle is a 90% gold sink :/ (you are only talking about
correcting the droprate and XP for the number of hits)
second I don't see the "extra" challenge of 10hitting compared to 2 hitting :/
the idea is still getting enough def or armor to prevent being hit, only in a
10hit combat the creature has 10x as much chance to hit you in the combat,
and an armor setup will result in 10x 1 damage, instead of 1x1 :?
that's where the idea of making the new buffs come into place or the combatmoves.
For instance in a real battle as an example your opponent can have a shield on, which takes all your attacks so you don't do any damage.
However if you then put a skill against it => dent shield, destroy shield, steal shield, the opponent looses the shield making the only option left for him to parry your attack with his weapon (the 2% miss for instance).
If you take it this way you can make the game so that you can force your opponent to miss, regardless of what your defense and armor is (even if it wouldn't be enough)
for instance:
creature has a sword and shield enhancement
you are buffed up in your setup, but due to the creatures shield you don't have enough attack to hit it.
you have the following skills at your disposal:
*dent shield: with a fierce attack, you hit the opponent causing his shield to show dents. Lowering the creatures defense with xxx
*destroy shield:in an all out blow you destroy the shield of your opponent. Due to the strength used, you can't attack the next turn
*steal shield: with a cunning move you are able to take the shield from your opponent. Opponent can't hit you for the next 5 turns, but your damage is lowered with xxx due to not being able to wield your weapon with 2 hands
=> this is an example of the options you have depending on your own stats and the creatures stats. If you lack a bit of attack being buffed up dent shield could be the solution.
However if you lack alot of attack destroy shield might be better.
If you then lack defense against the creature steal shield would be better.
These are all options you could encounter in a real life situation in combat. But the decision you make is based on what stat you lack against the other creature. So in a 10 hit combat it doesn't mean the opponent would have 10 attacks against you (steal shield, he'll only have 5 attacks, so if you go in armorsetup it would mean he'll do 5 damage, but you already have the ability to do 5 extra attacks where you can for instance boost yourself up or something like that. which in the end could mean you actually could be safe for the entire fight depending on your skill choice).
The option could be be entirely safe for 99% of the time but take 3-4 hits more, or go allout kill in 2 hits less but have a risk of 90% of dying.
Edit
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To take this even further and give champion monsters a bigger use might be that some combatmoves would only be accessible to you if you learn if from defeating for instance a certain amount of a champion. WHich would take longer to kill and be alot harder but, makes you able to use different setups in skills.
Same goes with elite creatures, currently it is making a large group, buff yourself up shield imp, high ca and attack the elite..., this addition could make elite's alot harder. And instead of only dropping equipment they can as well drop a "move" recipe