You just blew my mind. I'm not quite sure if you meant to say avoidance in a few places you put mitigation, but then again i'm no math guru.
But to comment on one thing I understood in there: your damage intake as a paladin is going to be a bit diffirent than another type of tank.
For instance, a warrior who pops shield block off the pull, like your paladin with holy shield, is going to start with little dmg incoming and build to higher damage as the effect drops (if it does). Conversely, a deathknight who did not drop two blood runes before the pull is going to miss 5% of his mitigaion while the first hit or two lands (takes at least 2 globals to dump the blood runes, but most dk's will start with plagues, so you end up with an average of 4 globals unless he pre-emptively boiled them off). A druid will take more damage on the first hit or two in a similar manner, unless his first hit is a crit (since he must crit to pop savage defense).
That's all very basic stuff and I won't pretend to have studied models of tank damage based on class, but as a raider and raid leader who regularly plays three diffirent classes of tank, i'm pretty familiar with their mechanics.
Per the crushing blow deal. What would lead you to question it? Are you suggesting that some mobs can crush a target that is not 4 levels below them, or simply implying that level isn't the sole factor in calculation?