Looking at modern apps, tools and software in general, we have to conclude that less is more. Or, rather, that "less is more" attitude stems from laser-focusing on your ideal users. Take email tools for example. Back when Outlook was king of the mountain, a good email tool needed to have all the bells and whistles imaginable. The more features there were, the better the tool was. It's not like that anymore. The best email tools are simple, focusing on a small range of features, and targeting a specific type of user. No matter if you want just to have a simple email tool, or use your email tool as a task manager, or want it to help you with productivity and moving emails around based on your daily agenda, then you have individual apps that will help you do that. They're laser-focused. There's just no reason to use have-it-all email tools nowadays since they mostly lead to distraction. So, if you need to solve a broken UI, the straightforward answer is to simplify it. Go back to your user's primary goal and how you can help them solve it. Remove everything else that doesn't make that goal easier to achieve.