It’s interesting that this topic came up twice today. See this post for a more detailed explication, but in short: one problem I kept running into when I was “transforming things in the constructor” was the fact that I couldn’t tap into the rich collection of resources that would ordinarily be available via DI. When I switched instead to moving all intelligence into providers and making all data-bearing objects be dumb interfaces, this limitation melts away, and the responsibility for doing the transformation moves to the service.