They could do here what they did with DAI, Dragon Age Keep. It's website where you can generate infinite amount of save files to import into DAI. Pick and choose how key moments in previous games went. Build in checks preventing any conflicts and offering options for user. There even is story recap stuff for previous games.
https://dragonagekeep.com/en_US/
Nah, I know about the Keep. I'm talking more 'internal development' aspects.
Like, if Bioware doesn't know what they want to be sticking points as of when Andromeda ships, how will they know what ends up being the 'important stuff' that deserves to be carried over, and how does that tie into the relevance of said plot-point inside the Andromeda game?
It's not 'necessary' by any means, but it definitely was a noticeable difference (to admittedly varying degrees in specific instances) in terms of of DA:I 'remember this' and ME 'remember this' moments that took importing into account.
Basically this:
Resulting in a series of absolutely incredible games. If they want to avoid the original trilogy's mistake, one would think planning ahead should be the way to go.
It depends on if they want to adapt DA's style of 'loose connected overworld where minor decisions may come back, but doesn't (generally) change the world state to the point of entirely different experiences', or ME's more tightly-enmeshed continuation (again, to a varied extent, depending on the specific plot point)