There was other threads talking about how Long Rest should come with penalties, like if you Long Rest in a dungeon with monsters about, then you should get attacked(similar to being abushed in BG1).
I don't think random encounters would be the best choice, it depends on how they are set up but with how the mechanics of the game is, a random encounter could spawn on top of you where you have no chance of winning it.
Maybe they could think of adding something like that after they have worked on the game a bit longer.
The problem with random encounters is that you can always load the game, which makes them a bit pointless.
