It would be interesting to have the timeline of galaxy shown.
We've got the tutorial, then the arcs with Twinshot & Dr Graves. Then unless i am missing something, you have the Payphone showing what's going on. So, nothing between 20 & 40.
Can't say I'm a fan of the phasing tech they use for storylines in Atlas & Mercy, though it's more interesting in Brickstown where if you've done the Marchand Arc, you then have Marauder near Manticore. Though the Brickstown stuff is purely decorative.
Maybe more like the PvP zones that set you at a level, so when you visit Galaxy you get a choice of which era you're visiting and you get set to that level?