Do you think Harmony is faking how impotent he is? For all that Sazed says the two shards he holds oppose each other too much for him to do anything, I have the feeling he is faking it, or hamming up how bad it actually is. The reasons I have is twofold, firstly, the shards of Preservation and Ruin have both been shown in their original holders to be thus far the best shards at both future sight and people manipulating. While the skill may not fully pass over, the potential for both are still there. And the second, for all that it seems like The Lost Metal went down to the wire, everything worked out in Scadrial's favour in the end. They managed to repel an attack from Autonomy, there has been massive strides in technology, from missiles, moving picture, and radio, and in magic due to Autonomy's scientists figuring out how to hemalurgically spike someone without killing them, and maybe even directly from pure investiture, removing the need for sacrifice entirely. This information will eventually make it to Kelsier once the Ghostbloods retrieve Shai, who witnessed the technique and can restore the near burned documents. Other people have also pointed to other choices Sazed made that greatly benefited Scadrial, him not giving Kelsier a full body lead to him pursuing hemalurgy, Kelsier's experiments with investiture eventually led to the Southern Scadrians inventing Unsealed Medallions and flying air ships. And one major thing which I have not seen anyone really mention, is that in BoM, Sazed let 'slip' that moving pictures are possible to the Kandra, who later mention that to the crew, and Marasi, who was able to use this knowledge to recognise the Set's moving film, and eventually realise they were using that to trick Allomancers.
Someone else on the forum said it first, Sazed might be a secret mastermind. But why doesn't he just directly move instead of acting behind the scenes?
Well, I have a theory on that, I'm not sure if this has already been raised somewhere, but I think it's because Sazed knows he is unprecedented as Dishardic holder. We've seen worlds with multiple shards, but a single person holding multiple only has Sazed as the example. I think Sazed is faking inaction because he realises that if he proves that a person can stack up on shards to little negative effect, it'll cause mass Discord across the cosmere as shard holders realise they can take another shard, alter their intent, and maybe become even more powerful. Sazed is following the intent of Harmony by keeping peace across the entire cosmere by sending the idea that you should not stack shards, or you'll be rendered impotent as the shards oppose each other. I still think Ruin and Preservation are still opposing each other, but I don't think it is to the extent that Sazed is showing and making everyone assume. And that he may really be indecisive, as Marsh and Kelsier can see, but not for the reason they think. Sazed may be indecisive because he realises that if he acts directly, he can maybe save Scadrial and protect it, but throw the rest of the Cosmere into chaos and Discord, every lie works best if it has a grain of truth in it. The one major example of shardic conflict are in Roshar, but we've also seen the aftermath in Threnody. Ruin and Preservation is a less direct one, because both had been weakened in some way, but even that had been horrible. Civilisation in Roshar was constantly slipping and dropping because of the constant Desolations and shardic conflict before the Era of Solitude. Shardic conflict are just horrible things to go through, and Sazed should know it most of all.
There may also be an element of self preservation, because he currently is the most invested entity in the cosmere, Odium feared him because of what he represented, that of the shards recombining to reform Adonalsium, why can't the other shards do so as well? But one thing we know about the other shards is that they are maddeningly passive, not even acting on Odium who is explicitly out to kill all of them just because he was trapped in Roshar, if Sazed sends the same message, that he can't do anything, then most of the other shards won't see him as a significant threat. Autonomy still attacked, but compared to the rust Honour, Cultivation, and Odium are pulling on Roshar, a single shadow organisation seems rather tame, Autonomy seems to spread herself very thin. The Set was likely a probing attack, with the Red and Gold Men deployed because Autonomy saw the weakness in Sazed and decided to get rid of the civilisation that had technologically become enough of a threat to her, not because of Harmony being dishardic.
I think Sazed right now is walking a very fine line, he's moving people to help fend off Autonomy, but he cannot directly act or else other shards may see him as a threat and team up to take him out, or try to copy him and cause massive Discord across the cosmere in their wars. Maybe the current shardholders won't, but shards can change hands, sometimes even surprisingly.
I'm not sure how coherent this theory is, or how true it will be, but I like it because it gives Sazed more agency rather than him being controlled by his shards. Him making it an active decision to not act in order to Preserve the lives of people across the entire cosmere has a better ring to it, and fits his title as the Hero of Ages a lot more. As shown by the shadow self, Sazed might actually be on the verge of changing intent to Discord, which might show the internal struggle within him to act, and accept all the consequences of that, or continue to not act and potentially sacrifice himself and his home world.
