I think we should not engage in a discussion declaring those who believe in the Qur'an and Muhammad (S) and consider themselves Muslim, as Non Muslims. Sure they have a different point of view about many issues, but we need not agree with them.
We have seen enough bloodshed due to this practice of takfeer (declaring others non Muslims). It does not do any good to any one.
We submit all to Allah and it is His domain to make judgments over anybody's faith.