I haven't read through the thread but i have a suggestion. It might be a bad idea, and one that has no immediate financial benefit to the club, but they could look at how loyalty/City points are awarded, meaning people receive some for buying a ticket, then a further amount for actually going to the game (if not them then somebody else).
A second idea might be for the club to be more transparent about how tickets are resold via secondary markets and about who gets prime tickets for the biggest games. Cut Viagogo out, resell unused season tickets seats to fans who want them, without a markup, but with the club taking any processing fee necessary from the seller.
The fact that there's a pretty hefty backlog of fans wanting season tickets, but swathes of empty seats at some games is a worry. Obviously it doesn't matter what fans of other clubs think, but there's clearly demand for seats which aren't being used. Clearly there are other factors such as late time changes, too many televised games, kick-offs too early for fans who don't live locally, too many games generally, but it'd be great if the club was a bit more proactive in sorting these issues out.