Ya, it's kind of a quixotic one there. Getting to max block takes up so much resources that there's none left for much of anything else, and if block DOES fail, which it will even with 90%, you're taking a full hit, so why not have pure damage reduction like armor or life/str stacking something. Then you look at doing bleed, and you're stuck with some pretty lackluster stuff. Though I was eyeing getting to 11 impale stacks and the mastery that gives you 6% bleed multiplier per impale... it just seems like you're spreading your points too thin/not focusing enough to get there.Don't.
I DO think there's something to doing a tank with impale stacked to 11 and... some skill or other. Maybe one of those new earthshatter skills... need to monkey around in POB some more.