I'm sure I used to be able to see the name of the current class and method when editing vb.net files - I can't see anything similar in VS 2015 Update 3.
Does anyone know if there's a plugin that would show me this info? Being able to see the name of the current region would be brilliant, too.
You don't need a plug-in; this feature is built into Visual Studio and has been since at least VS 2005. (Actually, it originated in the classic Visual Basic editor and was ported over to Visual Studio when the IDEs were integrated.) I'm not sure how it got disabled on your machine, since it is enabled by default.
Go to Tools → Options → Text Editor → Basic (or any language you want), and ensure that the "Navigation bar" option at the bottom is checked.
This will give you a bar at the top of your text editor window that displays the class and method names. It doesn't, however, display the region.