Feedback GroupTrack isn't extensible?

Was hoping simply inheriting from GroupTrack would work, but it seems it can't operate properly without the custom inspector, which unfortunately isn't public to inherit from.

Groups provide a useful feature for organization, but also potential for rule enforcement.
I was hoping to create custom Group Types that I could then filter for when calling GetRootTracks(), since using Group string naming would be unreliable and prone to user-error (and general string garbage creation).

On top of that, with custom Group Types I would be able to easily enforce custom Tracks only being allowed to be created in a specific custom Group Type. Ensuring safety in how the team constructs Timelines/Sequences without requiring fuzzy conditional checks that might fail.

I read in another thread from years ago GroupTrack "should probably be sealed", but I'm not sure why given its usefulness just like other features we can override. Simply exposing the Inspector type for it and maybe making a few extra virtual methods public would do the job and offer an even great amount of Timeline customization for users.