1) The subject line cannot be customized, It just follows the pattern of "You have been added to the [[ Insert Campaign Name ]] campaign."

2) The "Sender Name" of the affiliate welcome email cannot be customized.

3) The "Sender Email" of the affiliate welcome email cannot be customized.

Making all 3 of the items above customizable would be amazing for the affiliate manager, since our users are asking about customizing these fields.