Not sure about this year but historically they are always short tram drivers/conductors. Driving thru the throngs of totally oblivious pedestrians is really mentally challenging. Moving people efficiently has been a decades long problem. One solution, but not a perfect one, is not to fill the tram at the terminus and give people downstream a chance to board.
I suspect you’re right about people using them just to ride around. I would break up some of the longer routes, in particular the blue route, and require everyone to exit at the terminus. The creation of the express routes were a step in the right direction.