What problem does this solve or what need does it fill?

Currently for entities we serialize only id:

But this is not very expected behavior. For example, if you serialize an entity, send it over the network, and map it to an entity on another machine, this will not work correctly, because generation is skipped for serialization.

What solution would you like?

Fully serialize entities. It may only be redundant for scenes, but Bevy use DynamicEntity for them anyway.