[faeyanpiraat]

Would it be enough for the safety batteries at the motors to be only as big as to provide power for the aircraft for an emergency landing? Like for a 30 sec full thrust?

That might not bother the weight distribution that much.

[GravitasFailure]

Maybe? Honestly my weight distribution comment is a tad silly since complexity and weight are far bigger concerns, and two that just don't seem to have any avenue to go away.

[DuskStar]

Most batteries don't have the power density to output their entire capacity in 30 (or 60, or 120) seconds though, if I'm remembering correctly.