To simplify navigation across large flows I would like the possibility to move the board around rather than having to use the scroll bars. For example right-click, hold and drag
Also it would be a good feature to have som kind of built-in zoom-in and zoom-out feature. For exampel Ctrl + Mouse-scroll UP for zoom+ and Ctrl + Mouse-scroll DOWN for zoom-.
My suggestions above are the controls defined by Lucidchart a web-based schematic drawing program I use alot in my work.