A US/Canada couple has less to worry about. A small wedding won't hurt you - just make sure to make it look as special as possble, have some kind of reception or dinner after, and go on a honeymoon! Not doing these things can be explained away, but it is a lot easier to not have to.
Now couples where one is from a country where there is perceived to be a lot of marriage fraud: in this case I agree that a big wedding will look more convincing. Ditto if in the culture of the applicant a big wedding is considered normal, such as India.