I've been experimenting with a simple house rule when placing Monsters. Instead of always placing the Monsters adjacent to the Warriors, I roll 1d6 to determine how far away to place them. Now, Monster archers are still placed as far away as possible, but now the other Monsters might be placed a few squares away from the Warriors, depending on the size of the room.
This opens up some other options for the Warriors, such as running away without having to worry about having to escaspe being Pinned, or charging the Monsters and setting up an advantageous formation in the process. The result is more than dynamic than always forming up in a corner and protecting the Wizard.
Of course, Monsters that succeed in an Ambush are placed adjacent to the Warriors like normal.