A lot of the problem here is, Eighth edition has become increasingly hostile to infantry blocks. High strength template weapons, increasingly powerful thunderstomping monsters, and spells which hit every model in a unit can all casually decimate or destroy even a tough infantry block, and it doesn't help that I1 makes saurus particularly vulnerable to some of the most destructive spells. Even if they survive into combat, T4 and a 4+ save just isn't particularly resilient any more. Savage Orc Big'Uns are only one of several units that can easily inflict heavy casualties, especially with such overpowered Hex/Augment spells in play. My own experiences with them were very much that I was paying points for extra toughness and armour save that often didn't translate into resilience on the battlefield, in which case I may as well just have put down a horde of cheap skinks which still die, but give away less VPs when they do.