No sir.
Magic had nothing to do with the mental merging of Bruce Banner's split personalities. Peter David wrote Banner as having three distinct personalities. Bruce Banner = Super-Genious; Gray Hulk = Lustful, Cunning and Shrewd; and Savage Green Hulk = Impulsive. Brilliant writing really, as he showed the differences they had as well as the similarities. It was Doc Samson's "therapy" that 'supposedly' merged them in the Peter David written stories. I say 'supposedly' because 'Merged Hulk' was unstable. It was later retconned and ruined by Paul Jenkins who stated that the 'Merged Hulk' was only another separate personality.
Under Peter David it was suggested that Hulk's very existence was in someway intrinsically tied to magic, as some of his abilities are seemingly supernatural i.e. he can see ghosts and spirits, has an uncanny tracking ability, grabbing hold of intangible energy, he can locate the exact spot of the gamma bomb explosion that made him, returning from the dead by absorbing radiation (like any other supernatural movie monster), ability for body to adapt and breathe in water and out of space environments etc...