I have two suggestions to make Gantt chart more intuitive and powerful for a quick task planning and visualization.
  1. Provide option to open a single task and its sub tasks quickly in a Gantt View. This will help quickly focus on that task/subtasks for visual planning. This can be a popup with a Gantt view for quick editing.
  2. Currently Tasks and Sub tasks do not stay together on Gantt Chart in the same order as entered in the list view. There is no way to retain the desired order currently. Due to this the subtasks get ordered differently. This make it extremely difficult if you need to focus on one task and plan its sub tasks.