You are absolutely right. Besides the two magic ingredients of Patriotism and Cricket, Lagaan also accomodates a great love story with beautiful and well sequenced songs. In this love story it project the Indian Culture alongwith the theme of unity in diversity (how Hindus, Muslims, Sikhs,...can stay together peacefully). AND how can one forget about it's rejection of caste system through the character of "Kacharaa".
are we all forgetting Richard Attenborough's gandhi ?? i dont believe any of the movies mentioned come seven near it... from star cast to the sets... its an appreciation in true sense of the struggle the great leaders of past had. also i was surprised that there was no mention of Manoj Kumar's Kranti !!!