Fangraphs article on the KK signing: https://blogs.fangraphs.com/kevin-kiermaier-is-finally-actually-a-blue-jay/
Here's the gist of it:
"The Jays are stronger with Kiermaier than without, but it’s fair to wonder if they’d be better off had they simply kept Hernández. Looking at the projections, it’s a wash – Kiermaier and Swanson look to combine for 1.5-2.5 WAR, while Hernández can expect to finish in the same ballpark. In Teo’s favor, he provides that value from one roster spot, and he also comes with significantly more upside – he received MVP votes as recently as 2021. On the other hand, Toronto can afford to sacrifice some run production for the sake of run prevention. They finished last season with the fourth-most runs scored in baseball, but only the 13th-fewest runs allowed. Ultimately, it feels like Mark Shapiro and Ross Atkins just moved the furniture around."
I would agree with that but on the other hand Swanson has 3 years of control left and we also got a Top 10 prospect out of it. So if it's a net zero this year then it looks like a win moving forward.