Posting Yammer thread links in a Teams post should preview the Yammer thread
When Teams tries to preview a Yammer thread link currently, all we see is the default Yammer preview. Link previews for Yammer under this behaviour are near useless.
A better behaviour would be for the link preview to have the topic and first line of content from the Yammer thread.
Attached is an example to how this looks now when Teams creates a preview for a posted Yammer thread link.