I think this is an excellent idea, well done ASFC.
I hope that it is the case that the season ticket options and prices will be unveiled at the event itself rather than before, encouraging people to get to the club to hear it first.
What would also be great is if Dan or one of his media minions could perform a running commentary on social media for updates from the event to put out to those online who can't get there physically. Then a full press release/statement on the website post-event.
On the ticket issue I haven't been able to get a season ticket for a couple of years due to living out of the area and not making every game due to home miles being a 50 mile round trip. Unlike moneybags cashman I can't afford to buy the ST anyway and lend the spares to a mate
The flexi-ticket is a great deal which I hope is brought out again but would agree with Dave - issue it at the end of pre-season.