Fate and coincidence are the main themes of this movie.

"It was written"

I think you point out a valid sub-theme. Education, poverty and our perception of intelligence being influenced by class are present in the script.

But Fate is still the driving theme.

All the complaints are the product of people not being familiar with the standards/characteristics of bollywood films.

It'll be interesting to see how people in India react to this movie...I think it was just officially released today. Noone here has identified themselves as Desi and it'd be interesting to hear their viewpoint. I'd assume that, being more familiar with Bollywood movies, one would be more likely to accept/enjoy the fantastical script.