I am going to leave a small note up here describing the changes that have taken place since I first finished this project in the Fall semester of 2016. In August the following year, YouTube updated the design of the whole platform, cleaning it up and bringing it more in line with the Material Design guidelines. A few months later they stealthily added the capability to search through your Watch history (but not your Search history), though I can't pin down an exact date for when that rolled out.
And on February 1st, 2018, they added a quick list of recently watched videos to the Android YouTube app, enabling people to access their history faster than ever before.
Their redesign and improved functionality for user watch history directly mirrors and validates many of the points I raised in this project. I never expected to see any of my ideas make it into the official YouTube experience, but it's certainly a welcome change for someone who's had enough gripes about these issues to go as far as start a project on it.
Since Google revealed Material Design in 2014, it has rolled it out across its multitude of services, usually in apps first and then their web counterparts. However, despite having a fully themed YouTube app, the web layout has a poor implementation of Google's own Material Design guidelines and much room for improvement.
Tabs work best on mobile where it is intuitive to swipe between them. However, due to their web environment clicking on a tab instantly brings you to another page without an accompanying transition. They also don't reflect the top-level navigation found in the navigation drawer to the left, with only 3 of the 5 supposed top-level pages.
In typical Google fashion, a great idea is marred by poor implementation. Taken right from their own design guidelines - "avoid creating too many regions."
One round of usability testing with the mockups was done to analyze which parts of the interface were unclear and needed to change. Testers were asked to navigate through two tasks and insights were gleamed from their interactions.