Interesting. The lament is supposed to be a defensive replacement to the offensive smite evil I take it? Since it's no longer tied into an alignment (evil) it has become much more useful. I'm not sure if I would give it a sacred bonus to attack and damage at all, probably just work some other defensive enhancement into it.
Perhaps you could make it a full class replacement for the stalwart defender? During lament, they gain some form of defensive stance that scales with levels in addition to the DR. And then you could replace stigmata with defensive powers.
Just a thought. I'm not entirely sure what you're hoping to do with this class though.