Ok, but then what's the point of splitting it in the first place? The way I see it is to split your domain so that a team owns not only the code, but also the model, the data, the interface and the future vision of a small enough area. If a service owns all the data, then someone who needs to make any change is bottlenecked by it and they would need knowledge beyond their domain. So the key is defining the right domains (or domain boundaries). Unfortunately most people just split before thinking about the details of this process, so the split will sooner or later hit a wall of dependencies.

We need synchronous work flow and then asynchronous workflows. That was the primary reason. Now that doesn't mean it must split, but since we're running on multiple hosts anyway it wasn't hard to split off the asynchrounous functions to another batch.