iPhone mail doesn't show email address anymore
Clicking on the sender or recipient name from within an e-mail header of the iOS Mail app opens the contact information page. This is extremely unfortunate because sometimes a contact can have several e-mail addresses associated with it. In these cases, it is impossible to determine the recipient/ sender e-mail address from within the iOS mail app.

The only fix for this issue is to use a different mail app which doesn't coddle its users in such helpful ways.