One of the frustrating things about GrimRock I think, is that for most battles you're constantly hitting then sidestepping, around and around in circles until the foe dies.
As much as Im enjoying grimlock, this aspect of the game does get a bit tedious after a while
So a hack n slash mode would let you stand and fight your foes head on.
It would do this by decreasing all damage from foes by 50%. Likewise it would decrease parties damage by 50%, increase health regeneration and slightly increase the effects of protection.
Maybe a few other tweaks to avoid ruining the game balance, but I think this could result in longer battles with an emphasis on slugging it out rather than 'hit and run' tactics
Would it be too early to call the current mode 'classic mode'?

Anyway, my thoughts are that you cannot toggle between classic mode and Hack n Slash mode, only select one at the start of a game
I think it would also provide interesting replay value for the main game