This may sound extreme, but the ‘grade’ is beside the point (most other historical theories also get an F): the general public is not really open to a theory as reductionist as ‘historical materialism’ which doesn’t even get economics right.
Readers today won’t accept the account of religion given in such marxist histories.
The real point is to be wary of theories and to study empirical sequences which may or may not exhibit structure. The perspective in WHEE adopts this approach and is far more useful. One of the tendencies of marxist historical accounts is the tendency to jackknife against modernity and force the creation of a substitute, which is not likely. The point is to see that revolution, democracy and socialism/communism are prime productions of the new era of modernity. The marxist corpus really expresses this, so it might help to devise new world histories that reflect a larger perspective with the questions of values in history added to the chronicle.