I do not consider kyuubi to be the most important thing to konoha in terms of it being an asset to the village as a weapon. (It is afterall in Naruto's and only Naruto's power in how far he maximizes Kyuubi's potential for the village's gain.) Rather Kyuubi is the most important thing to Konoha in terms of the consequences of losing it...losing it to Akatsuki. If Akatsuki are able to extract all the bijous from their respective jinchuurikis and complete their jutsu, the game (more specifically, Konoha and the Naruto world as we know it) is over. Kyuubi being the most powerful bijou makes Naruto, as its container, the King.