Actually, Poussin and Rubens themselves had little or nothing to do with the controversy. The real protagonists were Jean-Aguste-Dominique Ingres (pronounced Ang) and Eugene Delacroix (pronounced Dela-croy). Ingres had been a student of the outstanding classical master-painter Jacques Louis David (pronounced Da-veed) and was 18 years older than his rival. The competition between the two split the French Royal Academy of Painting and Sculpture down the middle and continued largely unabated from the early 1820s until both men died in the mid-1860s. Of course by that time, the young Turks of Impressionism were deciding the whole matter was something of a moot point anyway. And while they might tend toward The Rubenistes color theories and painting techniques, they hated the academic arguments and classical subject matter of BOTH camps.
The fact is, neither side was entirely right or entirely wrong. Given the state of art, and painting in particular, in the 1800s, both sides needed each other. Drawing offered form and paint provided color. Without both there would have been no painting at all. The theories of hemispheric domination were, of course, unknown at the time, but the matter essentially came down to a left-brain/right-brain approach to art. The left side of the brain being the analytical side demanded careful drawing, adherence to scientific rules, even in matters of aesthetics and color theory. Dozens of preliminary sketches were carefully condensed to a single, tightly drawn image on canvas to which carefully muted colors were delicately added over an extended period of time. The right side of the brain, being the visual and emotional hemisphere, tended toward an instinctive approach both in drawing, and especially in color use. Drawing was done with a brush with wet paint swishing sensuously over virgin canvas, evolving into emotionally charged patterns of light and dark then to powerful masses of vibrant color and texture. Paintings were often executed, start to finish, in only a few hours of ecstatic painting frenzy. Today, not all that much has changed of course. The only difference is the names--the Rockwellians and the Pollockers perhaps?