Has anyone had any success setting a pickup point at departures rather than arrivals?
Uber drivers are supposed to meet passengers at a designated area which is a bit long walk from the terminal, so I was thinking about hopping on from the arrivals area after they drop off a previous passenger.
I'm arriving in domestic T3.

They won't pick you up outside the Priority Pick up Zone - they pay for the use of that and they'd cop heavy fines for picking up elsewhere.
The walk isn't that bad considering you've probably already trekked 2kms from your arrival gate to the airport entrance.
If you've got min 2 people then Uber to CBD is usually cheaper than the train (not to mention quicker, more comfortable etc) and way cheaper than a taxi.