We dropped the membership scheme? I'm guessing it was for cost cutting reasons, or were there other factors?
Personally I'd bring it back, I know I'd get one, even if I dont manage to get to a game. Just as long as the club gets my money. The vouchers that were normally used for buying tickets for cup games etc. I'd also add a few vouchers where you can bring along a 'friend' who can pay at a reduced price. e.g Member pays 18quid and the guest pays 15, or if its a kid, they pay 5.
Though at the current gate prices I'd say that for a random one off visitor that 20 quid is a little steep and couple that with our inconsistency this year, it puts off regular and new fans from coming. If in the hopeful/unlikely/miraculous* chance we were to go up this year, can we guess what our crowds will be next year? Double, 1 or 2K more?
*Delete as appropriate
Also add some vouchers that offer some discount at the club shop, just to encourage more people to spend their money at the club.
Of course the system could and likely would be abused by some, but most systems are never perfect.