Skulking around in the shadows acting through proxies because he didn't want to get re-killed, and the first time he took direct action (because the DO made clear he had no choice) he was dead AGAIN in seconds. He's been killed by an untrained wilder and a half trained amateur, and the other Forsaken clearly consider him completely unsuited for any kind of field action. The only possible reason to bring him back would be to make more Worms and gholam, but if that were a priority he'd have been doing that instead of infiltrating the Black Tower (though in that case Lanfear probably gets sent to the Tower in Exile and Balthamel to the Black Tower, since the former becomes irrational around Rand. )

EDIT: Stupid subjunctive; I don't see why we don't get rid of it already and just use the simple past for both. Most people already do it anyway.