Do you realise that just because there's a red marker on your map you don't have to run towards it? The biggest problem with exploration is accidently going the right way, finding the door to the next level and having to back-track to the uncovered bits of the map. With the "quest is here" pointer I knew to stay away from that bit and had an absolute blast uncovering every corner; it felt exactly like D2 - poking corpses, ransacking shelves, exploding tree stumps and occasionally crapping myself as I came across a named enemy with a huge mob of cronies.