It's still open world in the sense that there are plenty of places you can go to and in any order without being gated through a linear story line.

Even if you were to ignore my advice, it wouldn't be any more open world because travelling between these areas is always gated by loading screens.

My suggestion is merely to reduce the amount of loading screens between zones.

Instead of leaving constellation, loading Jameisom, getting on the train, loading the shipyard, entering your ship, loading the ship interior, taking off, loading space, going to your map, selecting warp to sol, loading sol, selecting a landing site on Cydonia, loading your ship interior on cydonia, leaving your ship, and loading cydonia.

I'm suggesting you fast travel straight from the lodge to cydonia. Cutting 7 loading screens down to 1.

Of course, I also recommend that you take time to explore the areas you're in.