Some classes could be like a variable width crescent wrench, but are instead a fixed width crescent wrench on account of how the mechanism for width variation was designed poorly and jams all the time. The part of these classes that causes the mechanism jam is indefensible, even if you can still work with them, strictly speaking. They certainly shouldn't be defended with "if you can't work with these, it is your problem", and it is that use of logic that I am criticizing. I don't feel that the sorcerer necessarily is one of these tools, Zeful appears to, and appears to feel that bloodlines are what's jamming the mechanism for width variation. I'd consider bloodlines something that has jammed mechanisms in the past, and that could turn the sorcerer into one of these tools, but they might be able to prevent that.