What would the path be had you been able to contain the light?

[Alleo]

I mean Emet wants to bring back the ancients, the rejoinings and destruction of the shards are just the only way they have found that could achieve such a result.

It would still mean that they murder every shard person for that. After all Ardbert as his own person stops existing after the rejoining. He sometimes still had some thoughts in Shadowbringer but he is a special case. All the other shards that have rejoined with the source soul dont get that.

Also its not just the people. The world and its aether is sundered too. I doubt they would want to live on a sundered planet. Who knows if that planet could even endure them and their creation magic.

And never forget that in the end the Ascians were still tempered.