This feature looks promising. While it is a good start, I have 3 things on the wishlist to improve this further:

1. Trim content: When I forward the last email of a long conversation, it also forwards a lot of useless information about who sent the previous emails, what time etc. that could be trimmed with a simple toggle like in Gmail.
2. Images and signatures don’t appear like they should
3. Ability to forward mail on the same thread based on the same subject name. That would be helpful to organize the emails.