This characterization in turn suggests that predicting whether a connective should be included might be a difficult problem for an NLP system to address, since current-day systems lack the requisite world knowledge and capacity for inference that would be necessary to evaluate the ease with which coherence relations can be established on arbitrary examples.
it is also possible that the decision to include a connective depends in part on stylistic and other types of factors as well, such that there might be predictive information in the kinds of shallow linguistic and textual features that systems do have access to.