Do you use the mono version (c#) in 4.7?
You could try to delete your shader_chache in the .godot folder, maybe the “imported” folder, too. Godot has to be closed first, on next start Godot will rebuild the shader and reimport the assets. Maybe make a backup first.
Start Godot from a terminal, are there some messages? Does Godot detect your GPU, on run the first lines in the output.
It’s a sacrilege, but you could try GDStudio (closed source fork of the GodotEngine)? There the loading is way faster. I hope the loading optimization will find it’s way back to Godot.
Honestly, I’d say this is worth logging a bug about. Sooner or later someone else will likely also have this problem, and that’s where they will likely hunt it down, with multiple people reporting it. You might also get help with how to diagnose it.
A few questions:
Are you using Godot Mono? For future reference, when reporting your version that’s part of the version.