This coupled well with the mechanic where enemies would disappear permanently after defeating them so many times. If you decided to grind an area for levels after awhile you would run out and need to move on or burn an ascetic to get them back... But harder.
I kind of liked the disappearing enemies thing too. If you were struggling it sort of gave an adaptive difficulty. There were one or two areas where it was a fucking relief not having to do a fight on my way back through.