I'm actually wondering how viable it is to stack purely vit and %life for your mitigation as a holy crusader. Assuming you can at least take a few hits- any number of holy damage ticks should provide massive heals with a huge health pool.
The real problem I'm having with toughness is that min maxed gear allocations typically leave little room for it. Yeah, I'm gemming it full on now, but with only 4 primary stats and the desire to pursue main stat, cc, cd, as, element dmg, skill dmg, cd reduction, resource reduction, etc. wherever possible, it's hard to make room for vit, % life, and ar. (And don't even think about trying to fit life regen/life on hit or area damage in) The change to having designated allocation on gear for secondary stats (as opposed to the 6 primaries you could roll before) and expansion of primary stats into even more offensive stats- which, while maybe not that useful for other classes, are certainly good on crusaders, cr in particular- has me leaving ar on maybe 1 or 2 pieces. If my cindercoat needs its bonus fire damage, my andariels needs both that and cc/as, and my boots need spender dmg, where am I supposed to get it?