Obi,
The way I understand it now, is that the FBW system will maintain a constant vertical acceleration when the sidestick is neutral (in the Y axis) (as long as the bank angle is less than 33°)
Therefor, if you are climbing at 15° pitch up attitude, and your vertical speed is constant, the vertical acceleration will remain constant aswell (=0)
I think the whole concept of "1G" is a simplification Airbus made to ease transition to the FBW Airbus. 1G simply doesn't make any sense as soon as you have a bank angle...
So, at least as I understand it, the FBW will maintain a constant vertical speed when you let go of the stick. Does this make sense?
Regards,
Mark