I think the 2-week trial should be left just the way it it.
Why?
Aces High isn't a game that receives a lot of attention, nor is it very well known outside of a limited group of people who are interested in World War II aviation. Because of this, when updates etc are released, they're unlikely to be publicised or reviewed on the big gaming forums/magazines etc, which AFAIK is where most people would go if they're thinking of getting a new game.
This is speculation on my part though, however I still think it makes sense.