It should be easier to pay for your journey. At present the fact that First do not provide change or make it easy or even possible to buy online is an issue. First not offering change on-board is a massive frustration.
There is a big issue with anti-social behaviour on buses ranging from those that compromise comfort to the criminal. Some examples include: people flouting the smoking ban; drinking alcohol; behaving aggressively/violently towards other passengers or the driver; having gratuitously loud conversations with people around or on mobile phones; mobile phones not on silent; playing of loud music either through headphones or without, and littering. Support staff on-board and an arrangement with the police to patrol the bus network could help.
A big improvement in information is needed. The quality of this at bus stops and on-board First buses is variable if even existent. On once occasion I emailed First to tell them that there had been a lack of information about changes to services and the response was denial and bemusement, because they had apparently distributed booklets (which turned out to be very uninformative and inaccessible) at stops and on-board (not very helpful if you haven’t got on the bus yet) that I had never seen. Some drivers are also not knowledgeable or friendly. Something like Transport for London’s excellent website would be good, where you can type in your start and end points and receive journey details across various forms of public transport.