If I disable shadow copy (UsePluginsShadowCopy -> false) then I get multiple exceptions from the plugins not being able to load plugin assemblies. For example Nivo slider widget cannot find Nop.Plugin namespace...
When disabling shadow copy and running the web site it seems that the Razor view engine is trying to find Razor precompiled Views. I assume that this is because it finds the deps file that is generated and moved to the Plugins folder. I had to use <GenerateDependencyFile>false</GenerateDependencyFile> in order to skip generation of the Deps file for every plugin project that contained some type of View.
Alternatively one could alter the Clear Plugin Assemblies task to delete the deps file too.
Nopcommerce 4.10 with Shadow copy disabled seems to be working right now, too soon to be 100% sure.
It would be awesome if it could work with shadow copy and "CopyLockedPluginAssembilesToSubdirectoriesOnStartup" enabled as it makes deployment of plugins somewhat easier.