CLANNAD, like Kanon is based of Key’s story/dialogue driven game. Kyoto Animation has given us a preview at the end of Kanon. The animation will be similiar to Air, Kanon and Haruhi with beautiful instrumental and piano music taken from the game.
This will be something to look forward to because CLANNAD has a much deeper story with University level dialogue, but will a movie or 13-26 episodes be enough to express this story (which is many times longer than Air and Kanon)?
So does this mean we will see a Planetarian anime soon? If they do it will be for completetion purposes since most of their games have been animated and with great success.