Re-implement "click on send to show all their emails"!

Re-implement "click on send to show all their emails"!

Why in the world did this feature ever get removed? It was one of the most uniquely helpful features. Conversation view only picks up mails with the same subject line. Subject lines are crucial for organizing mails, and being able to click on the sender and get everything that person had ever sent was great! Re-implement it please!