I have a FOSS project called Open Payment Host[1] which removes the payment hosts from the equation and removes the technical hassle of integrating multiple payment gateways but it does not solve the pain of having to deal with the payment gateways and by extension payment processors and banks.
My long term plan is to integrate direct banking API where ever it's available.
Is there any bank from any country which provides direct banking API to end customers for plain savings bank account (I've seen some provide for current accounts).