Unfortunately, YouTube recently disabled it's video editor in Creator Studio. Blender, like you said, is a very good program but it was designed more for 3D scene creation/rendering and for that reason not as convenient to use as a video editor, but certainly capable. Your suggestion for Shotcut is a very good one! Especially for most people just getting into rendering their own videos as it will provide everything most people will need. For more advanced work in 4K I use Kdenlive, which in my experience is easier to use and works better than Lightworks. I use Linux so I can't report on how well Kdenlive works in Windows. For people willing to try Kdenlive, there is a wonderful community of developers and users on G+ that actually respond to questions. Oh, and did I mention that Kdenlive is free to download and use? Greetings!