Seeing as how in the survey I completed included some specific questions about timeline and how tasks get ordered, my other thought about how to improve timeline (beyond having a timeline view for all projects and how they interact with each other) would be the ability to exclude certain tasks from timeline view. I know that when you originally set up timeline, you drag tasks onto the timeline, but I think its annoying to leave them there; and there isn’t a way to remove them once you’ve placed them in timeline (that I know).
My thought would be for a feature to basically exclude a particular task from view. For example, a project I’m working on entails more informational tasks (purchase orders, their status, etc.) which I don’t want to see on a timeline, but care for when those purchased items get installed, programmed, etc., which is a separate task.