Let's generalize that it is a reading app, so one of the principles we are following is to keep it simple, intuitive and with the text in focus. The example shows something like a "song book", but there are other types too.
The current design uses a navigation drawer and the proposed design ( a quick mockup using developer tools ) uses a tab based navigation. So there are some problems:
- Almost all¹ older designs uses navigation drawers, so users are already used to it. In the other hand possible new users aren't.
- It need to be adapted to be easy to use on using only the mouse, only touch or only the keyboard: some users prefer just to use the keyboard, others just use it when searching, and on mobile there's only touch.
- Have a persistent search box like Google Developers/Tumblr designs, a dedicated page like Google Design, or a expandable search box, like many appl