"Build/Package/Release logic is complicated, and deserves sophisticated tools and abstractions just as much as the code it builds."
This seems correct until you realize that the #1 priority for your build system is to not be spending time screwing around with your build system. The benefits of using Maven to stay with the herd ends up dominating any benefits power you get to come up with clever build mechanisms. Then, yes, maybe you have an ugly shell script you have to run in your CI--but for all the crappiness of that, it's still composed on top of the thing that you basically never touch.
I've heard first hand from one big marquee Scala company (you could get it in a couple guesses) that this was basically why they were going to move away from SBT. That was years ago, so do with that what you will.