I haven't been a proper sapper yet (I've tried one once on a siege map, but it was La Haye Sainte and since we were all rushing straight in, and I hadn't enough points for a crate, I just attacked the enemy with my axe) but I love the addition of them to the game, making useful and enjoyable little defences for vulnerable spots and redoubts for artillery. They are a very successful addition to the game in my opinion. They can do cool and useful things like the OP showed.