The problem with NuGet is that installers don't always update assembly binding mappings.
As I mentioned earlier, I'm trying to upgrade a very large project to a new version of the ASP.NET runtime to try to solve a lingering problem. This required updating somewhere around 20 NuGet packages, only some of which make correct changes to configuration files.
I've just gone through a 15-minute publish cycle that ended with an old and familiar error message for old and familiar reasons.
Guys. Quit messing with my configuration files. But if you have to, do it correctly. Seriously.