Ability to Access All Timeline Activities from within SP and CTA

We are heavy users of Timeline and Success Plans, and have a request for the ability to select to view all Timeline activities from within the Timeline section of Success Plans or CTAs.  From the end user perspective, I want to be able to review previous timeline entries as I’m getting ready to track my current activity.  I know it could get noisy, so maybe an option to toggle it on/off. 

Maybe this would also be a place where “pinning” or “starring” would home in handy.