Visual aids are super helpful. I find the newer player you are, the more helpful it is to have a visual aid such as 3D terrain, or a battle map. The longer I play, I find that the 3d expensive stuff simply enhances my experience, but isn't necessary for my understanding of the game.
Very cool ideas here! Especially loved the concept of giving lower tier monsters added lair or legendary actions. I immediately thought of if a bandit hideout that is filled with traps that they can activate to hinder the party and get away!