Gil Student tries to pin down what Modern Orthodox people believe (though he mixes the terms “Modern Orthodox” and “Centrist Orthodox”.)
The problem with that is that it's much easier to define people fairly accurately by a label the farther to the religious right they are. Charedim have specific hashkafot in place for the various groups, and complete adherence is expected of members. Centrist Orthodoxy is a little harder to pin down onto a range of individuals and by the time you get to "Left Wing Modern Orthodoxy" or "Open Orthodoxy", there's not much of a party line and the mass of individuals represent quite a spectrum of beliefs.
Personally, I like it that way. It forces people to get to know one another as individuals instead of projecting a label on them.