Neutral?? BS. Depends on the mainline. Maybe at the ALPA airlines that have prostrated themselves in front of their managements and given away productivity and scope, but not all carriers.
DALPA wants a 9 hour fly day because the the senior guys that rule it can do longer day turns and work less days at the same flying time at the expense of everyone else. Just like giving away scope. Doesn't affect them, so screw the junior guys.
And you base these wild-ass assumptions on what in-depth research, exactly?