Thanks for elaborating.
You can achieve at least part of what you describe by making your subclips "soft." To do so at creation-time, in the Make Subclip dialog, uncheck the option "Restrict Trims to Subclip Boundaries." To convert an existing "hard" subclip, access the Edit Subclip dialog (Clip>Edit Subclip, or right-click>Edit Subclip, or define a keyboard shortcut and use that) and uncheck the option.
Soft and hard subclips behave differently in two notable ways:
- when you doubleclick a soft subclip in the Timeline, the Source Monitor loads the whole clip. The zoom/scrub bar is zoomed in to the In/Out range of what's used in the sequence, but you can zoom out to view the whole thing. Note that Match Frame does not load the clip in the same way--you're not able to zoom out. However, double-clicking a clip automatic matches frame (if the playhead is over the clip you clicked).
- You can trim out beyond the defined Subclip Boundaries, either in the Timeline or Source Monitor.
Now, if you want to create a completely new subclip for a different segment, there's no direct command for that, but it's achievable through a series of steps that you may find easier than restarting from the original master clip. (Almost all of the following commands can be executed via keyboard shortcuts.)
- Reveal in Project (from Timeline or Source Mon)
- Duplicate
- Load the dupe in the Source Monitor
- Edit Subclip
- Select the option "Convert to Master Clip" checkbox and click OK.
At this point, the whole clip will be loaded in the Source Monitor, zoomed to the subclip's In/Out range but without In/Out points set. You can set new In/Out points, then save a new subclip.
As to why PPro does not maintain a master/sub relationship, I'm afraid I have no clue. I'd say it merits a feature request--both to maintain the link and, naturally, to provide a way to jump from the subclip to the master. You can submit such a request here: http://www.adobe.com/go/wish