Sorry I wasn't clear - mixed nomenclature > me.
What I should have said was pure avoidance. Your example actually furthers my point. In heroics dodge is better than +block rating. To some extent, obviously. you're going to want to block some for threat but a greater chance of completely avoiding a 4k hit is better than only taking a 3k hit (totally making up numbers but you see my point.
What I'm saying is that not having to beeline to uncrush gives you a little more room to play with your pure avoidance. +Def and +Block Rating being the easiest ways to get to 102.4% - if that's not your concern you can afford to throw in more dodge for pure avoidance.