A couple of things to be real about:
1. No random encounters is clearly a major design decision, consistent with DOS, and unlikely to change even if Larian is listening.
2. Random encounters almost always just annoy, slowing you from what you want to do, especially in a game with anytime save/load. In an RPG where you grind for levels or gear, e.g. FF or Diablo, it's core to the game.
Changing mob positions, patrols, or other AI strategies would spice things up for replay value.
