We can see incoming email conversations in the inbox but don't have the ability to send a quick reply as the user the email was sent to. Realistically when some of us manage emails for a co-worker or boss, we need to be able to reply in the email conversation as the person the contact was corresponding with. Right now we are limited to only the email assigned our particular user/log in.

SMS already supports this. We can respond as any number from the users. We just need this flexibility with email.