Actually, I think what the book does (or tries to do, judging from how it apparently failed on most readers) is to illustrate the Clan approach:
(False) Thomas Marik and Paul Masters discuss the Clans who, at the time, are outlandish invaders on the opposite end of the Inner Sphere who have far superior technology and utterly strange ways and beliefs. And who have no qualms about flattening a city if need be.
In the beginning, the Clans are portrayed as powerful, unpredictable and dangerous.
At the conclusion of the book, through the horrors Masters has experienced and fT Marik witnessed (vietnamish guerilla war, nukes deployed by Joe Average), they come to the conclusion that the Clans' approach with formalized warfare is the preferrable option. The Knights of the Inner Sphere, after all, have a similar honor system and have it for exactly the same reasons as the Clans. Someone even points out that the Clans initially try to spare cities, and only fight dirty when forced to do so - it's only when pressed by the defenders that the Clan gloves come off.
WoB, on the other hand, never learned that lesson (save for Precentor Blane, who eventually vanishes). They opt to go down the opposite road. A few years later, when they have finally sorted out their internal differences, that makes them what they have become. In the sense of understanding the Word of Blake, Ideal War is probably the most important book to read.
