EDPDragon

Yeah Nale is clearly still incredibly unstable, he's the prime evidence that bonding probably wouldn't do much for the Heralds, thank you. When Ishar was sane for a moment he told Dalinar a radiant swearing oaths nearby may temporarily grant moments of sanity, and as we have seen "temporarily" means at most few sentences worth of sanity before reverting back to madness, so it would in no means be a viable solution for the Heralds.

There's a trend between the ideals sworn by radiants and the heralds gaining moments of lucidity, if only for brief times. Would a herald that attracts a spren and ascends multiple ideals be able to more permanently heal their madness? I'm no expert, but I would assume it would be especially difficult to get someone who is mad to achieve a bond. The state of relations between heralds and spren might make things difficult as well. Spren might have harsh prejudice toward heralds similar to the honorspren's refusal to risk bonding men. Also to be taken into consideration, Nale has also already bonded a spren and ascended to the most difficult and powerful 5th ideal, and he still appears insane despite getting a bit better in his encounter with lift. It could be possible that personal nahel bonds can make the madness less extreme, but not a complete cure.