I strongly favor massive and ambitious total-conversions and I even tend to rant about them from time to time, but I think it might be good for me (and newbies) to start something small, without custom assets and small missions.
Should I leave Shattered Stars for the time being? Or I find someone who can? Or I continue to work on it as if it is like BP:AOA?
That sounds like an awesome plan. Start small and build your skills. Even though AoA was a one-man project, I doubt that was the first thing Darius worked on. Seems like I saw that name a lot when I was reading about Inferno in my early HLP days.
As your skills grow, so will your ability to introduce new assets and FSO features into your work. That will also give you time for your SS storyline to gel, resulting in a more consistent and enjoyable experience when you resume working on the mod.
That sounds like a sensible suggestion so far. To do otherwise is to ruin the mod itself. This is an issue for not just SS, but also potential projects such as the untitled Galactic Rim Worlds game, the untitled true
Galaxian 3/UGSF mod, and the FreeSpace version of PlayStation All-Stars Battle Royale and Super Smash Bros. Non-TC ones like the Total Recall 2012-based game, FS:Reunited (to be based on SS), the Ender's Game-based game, and the Regime game are also affected.
As for the greater SS storyline, there is more than one side to this. SS:ADW takes place in an alternate universe, the same universe as the currently-desolate Earth where the 2018 Mortal Engines film takes place. The greater SS storyline is primed to be the logical epilogue to the FS saga, following Blue Planet.