On one side, giving them shield block for free makes it a little easier to roll a griefy thief that can focus on stealing and on being very hard to kill. Not that the ten points is a major deterrent for someone who wants to make this kind of char, but it does mean maybe trading off a little in a secondary path.

Still, them having it for free probably makes more sense, or at least lowering the cost to 2-4 points. I get that it is an always on defensive skill, but they are the only one of the five (non-orc/goblin) melee classes that do not get all three of dodge, parry and shield block. (ranger, bard, warrior, assassin all do)