I have an interesting thought. Of the two dawn shards we know they seem to match one shard really well. For example, change matches cultivation almost perfectly and The exist shard matches preservation very well. The hypothetical bind shard from the Poem of Ista matches honor, whose oaths bind anybody. I believe that this is not coincidental . Instead, I believe at the shattering, Cultivation used the change dawnshard, Preservation used the exist one, and Honor used the bindshard. This usage influenced the shards that they chose. Thus their intent are extremely to the shard that they bore.