Is the only way to pay affiliates via generating a payout manually? Will the API version be included in future releases?
Technically, it is not a problem to implement this. However, there are security reasons to not do that PayPal does not allow any fine-grained access control for API users. To make payout, it is necessary to store paypal API username and password somewhere inside aMember. This username and password (potentially) allow to take out all money from your account and send it somewhere else. Now the question: do you REALLY ready to store such information on a shared hosting server? If any script on your website (not necessary aMember) is hacked, this information can be retreived and used by hackers to nullify your PayPal account balance. That is the reason why we do not implement such option and do not recommend to use scripts having such option.
Currently you are able to download PayPal MassPay file, upload it to PayPal. Yes, there are 2 additional steps, but once in a month it usually not a problem to do that.
I agree with Alex, I've been doing the manual mass pay thing for years- really is easy and fast. Not more than 5 minutes. David