Gnash will never be as functional as Adobe Flash Player, because Adobe also develops and changes the flash format constantly, and doesn't publish the specifications of the format. Because the format is a secret, Gnash is developed using reverse engineering, which is a very slow process. Even if after an year Gnash is written to be 100% compatible with the current version of the format, Adobe would have released several new versions by then, and Gnash will still be behind.
In a sense, Gnash will never be "mature".
