Wow, didn't know there were so many desis on the board (parents emigrated in the 60's and I was born here)!
The poverty of 70's Bombay was the main focus of the movie. That is, a "slumdog" who lived through some of the worst experiences, who made something of himself (even though he was just a chaivala) and got a chance to become a millionaire. I agree that the modern Mumbai was shown to be a modern, up-and-coming city, but not without the poverty of any modern city, and that's probably what FiC missed.
As for myself, I liked the movie. I didn't think it was great, but I love the attention it's getting.