So far, the evidence tends to support your suggestion. For example, the overlap between DMDD and ODD is extraordinarily high (e.g. Axelson et al 2012; Copeland et al 2013). In a clinical sample of children selected for significant temper outbursts, ODD criteria were met for 88% (Roy et al. 2013), whereas only 22% would have met criteria for DMDD. As Copeland and colleagues (2013) note, the evidence for the distinct clinical utility of DMDD is still lacking. A 2012 paper of mine in the Journal of Child Psychology and Psychiatry suggests that irritability may be better represented as a specifier of ODD, in accord with your suggestion, Susan.