Wargaming is apparently working with Microsoft to streamline the certification and quality assurance process to make sure that the game will launch later this year. The game will miss its estimated launch of the end of the summer. The estimate of an end of summer release was wishful thinking as the developer continues to update the game to tweak it.
Making a judgment about the 360 version based on the current beta would be unwise. The developer is all in on this project according to sources we have spoken with and they are not going to rest till the get it right. That is good thing as it would be less likely to make any money if the free-to-play title on the 360 is riddled with problems.