Current usage for blocking generals
Actually slow generals are used usually (in few guides I have seen veteran general in some blocks). When using slow generals the main target to make a good blocking is to use the general in a simulation where you win the 100% of times. Why? because the destruction of the camp give you 1 extra turn... if the blocking time is 5-8 (7.33), it will act as 6-9 (8.33).
What is happening with the new general?
Blocking with new general (Master of defense) is different.. why?
You need to use another aproach for combats with him. The main feature of this general is a very high life, and a small hit. In combats, general is the last unit killed. With this in mind, to raise the number of rounds to the max we will need to destroy the max number of troops, but we will search combats where we lose the 100% of the times. Defensive general will need a lot of rounds to be killed (few enemy troops = small damage).
Lets see a fast example in horse back.
In first campament A1 (70 nomads and 40 lance riders) we would have with normal general and 48E
4-10(5.66), with 99.00 win %.. that means 5-11 (6.66) rounds.
With the new general, assigning 42E, we get 11-23 (17.55) rounds
Just by setting 1E more .. 43E, it just drops to 6-22 (17.03) rounds, still a nice average but the min rounds dropped to just 6 (dangerous). This is because we win at least one of combats in simulations (my sim does 10k simulations).
The important thing to remember is that we get the extra rounds where the general is alone against a small number of enemies.
VERY IMPORTANT: The new general is a fast general, this means that rounds last for 10 seconds instead of 20, keep this in mind.. because we will need at least 2x times the number of rounds for a longer blocking attack.
You can use my simulator to do your own tests.
http://settlersonlinemaps.com/fastsim.php?LangCode=2
Best regards