It seems the Forsaken are usually somewhat constricted and not allowed to massively attack main players on the Lightside yet, because they seem to be more valuable as pawns, e.g. Egwene (the Cleansing was an exception, though, and Moridin at least gave the order now to kill the other two ta'veren). This is also illustrated by the fact that Moridin even personally saves Rand's life during the confrontation with Sammael in the end of ACoS. I really hope all this will make sense in the end, when/if we eventually learn the real "master plan" of the DO.