No. He was not. He doesn't know the motive for the crimes, he doesn't know the butterfly effect of the means of murder he wrote and was simply a delusional prick.
SPOILERS ALERT IN WHAT FOLLOWS IN THIS POST
A real G with the death note wouldn't just target criminals, nor would they inherently assume that they'd outsmart the best detectives on Earth in such an 'in your face' manner as Light dealt with L, Near and Mello. Light Yagami was a fuckboy who thought he was a godfather of crime (ironically) and got schooled by real masterminds in the long run, who evern gambled on and planned their own deaths and defeats to him along the way (as evidenced by Watari's forethought, training of multiple L-like detectives and the transfer of documents and such to them post-death).