A lack of any real interactivity with the terrain has been a long-running weakness of GW games. It's fine in their army games, but it really does hurt in their skirmish games where there's practically nothing to do except maneuver around the board and engage the enemy.
My tip for painting terrain is : use rattle cans and craft paint, and don't worry too much about little mistakes, the goal is to get it done and on the table. Your minis are the star, not the terrain.
I've absolutely packed my necromunda board with terrain, there is that much it's kinda difficult to play on it but it's definitely realistic. My ash wastes board is alot more open tho for obvious reasons but the two boards are alot of fun to play on
