Right, I meant it would be awesome if Blender itself had the ability.
However, I actually discovered something very interesting. If you duplicate a window out (for me, the 3D View) and make that VSE, it will become disconnected from the active scene. Effectively, the duplicated VSE becomes a global timeline, and the contents of the original window are “local”.
Meaning… you can change the scene without changing the contents of the sequencer! This little discovery is going to make my life easier. =D
Only thing is it doesn’t work in 2.8, so another reason (aside from the horrible VSE+scene lag) I won’t be using 2.8 for animatics right now.
Edit: Not true, just have to go to Window -> New Main Window to have the same behavior.