Your thumbnails are great, I love those. The banner could use some work but that is entirely up to you. I think it should have a bit more to it along with links to twitter and what not. And especially fix it to where it's not cut off.
I like your videos, the only problem is length. You'd have a lot more content and more time to dish things out if you made them at least 10 minutes or less. Plus, not many people would watch that long.
Also, if you make them shorter, your view time goes up which will help your channel get out their as YouTube favors channels and videos that people watch longer.