Why is Ishi the patron of Bondsmiths

[Jedal he/him]

I get the whole "guiding" ideal. But wouldn't Jezrien be a better fit? Like Ishi and Jezrien switched?

[AerionBFII he/him]

Ishi's Surges match the Bondsmiths Surgebinding, same goes for all Heralds and KR.

Also: 

Quote

"But as for Ishi’Elin, his was the part most important at their inception; he readily understood the implications of Surges being granted to men, and caused organization to be thrust upon them; as having too great power, he let it be known that he would destroy each and every one, unless they agreed to be bound by precepts and laws."

Doesn't sound like he gave them much choice.

[Pagerunner he/him]

Dude, we haven't even met Ishar yet.

In all seriousness, the spren imitated what Honor did with the Heralds. Honorspren, who are attracted to people like Jezrien, grant the same powers. The second Bondsmith oath says to unite instead of divide. Here's my interpretation: that's big-picture leadership, not just "I will be in charge." Windrunners lead from the front. Bondsmiths lead from behind.

[Spoolofwhool]

Also, they're probably also patrons because they hold the same surgebinding powers.