I don't understand why the Mail app doesn't have a "request read receipt". Is there a way to enable it through terminal or by 3-rd party add-on? If there's no way, I'm going to have to switch back to MS Outlook 
I do not believe that to be true.Since most SMTP servers strip these headers in their default config anyway
I do not believe that to be true.
Read-receipts are basically just a courtesy e-mail sent by a client in response to a specific header being set. You really shouldn't use them because they tell you nothing anyway.
It tells me that my email to a student was read, and that he'll have no excuses when he comes to class without his assignment next week.
It isn't. However, no client apart from maybe Outlook sends read receipts by default. Most don't support it at all.
Read-receipts are basically just a courtesy e-mail sent by a client in response to a specific header being set. You really shouldn't use them because they tell you nothing anyway.
Receipts are an artifact of the early days of America Online. To the extent that they do anything at all, they are most effective within a single domain. By this, I mean those cases where the sender and recipient are on a single domain. That said, I have to agree with CyBeRino. Receipts do not tell you that your recipient read your email. From the perspective of a recipient, receipts are annoying and are a clear indication that the sender does not trust you.It tells me that my email to a student was read, and that he'll have no excuses when he comes to class without his assignment next week.
You don't understand read-receipts.
First of, who says "you shouldn't use them"? You? Sure, then I'll take the advise.
Second, who says most clients don't support them? You? Well you sure don't know what you are talking about.
This activates read receipts for ALL outgoing messages - regardless of the address from Apple Mail
I forget the source - but it works.
Quit Mail
Open Terminal (/Applications/Utilities/)
Enter the following text (make sure to keep all quotes exactly as is!)
defaults write com.apple.mail UserHeaders '{"Disposition-Notification-To"="your@address";}'
(of course, using your correct email address instead of "your@address")
All future messages sent with Mail will now include the Disposition-Notification-To header which is the one asking for a return receipt.
If you wish to turn off this feature in the future, type the following in the Terminal:
defaults delete com.apple.mail UserHeaders