The new civic is already getting long in the tooth, its so increadibly fugly and cheaply built thats its sales will continually decline. I predict that next year civics sales will be -30/35% compared to 2005.
Back on subject - I think its not a bad decision for Toyota. While the Corolla is nothing exciting, it is a very decent car, and actually looks like a real car, unlike the new Civic, which looks like a soap box. And besides, Toyota just launched the Yaris, so if they release new Corolla now, it will steal some momentium from the Yaris.