Just out of interest, but would it be feasible to have a small passenger operated top up machine on board buses? Save on space so make it no change given, whatever notes/coins you insert is what get's added, so all it needs is a lock box for that to drop into.
It won't really speed things up for those who try and get on the bus with a negative balance, but for those that just want to add when they're getting low it could work.
When I was in Nottingham, not sure if they did top ups on their buses, but that's how the buses I used did paper tickets. Just drop coins in until the driver could see you'd put in enough for whatever the fare was, then he'd hit the button that dropped it into the money box that he couldn't access and he'd hand over the ticket, no change given.
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On the topic of weekly tickets, it depends on how you view what they were provided for. If you see their purpose as something to cut down on the number of transactions at a ticket window/machine, then yeah, no point or need for one now with go cards. But if you saw their purpose as something to encourage repeat use, then yeah there is a need. Currently that's the 9 then free, and to some small extend would be Simon's 3 journeys in a day then free daily cap.
What about something like if you do more than X journeys in a week (say 12 or 14 or something) then you earn a discount for all of next weeks travel (say 5-10%)? Not useful for the occasional commuter, but it's something to drive ongoing use.