Technology was more advanced, but Thrawn was fighting the people using those machines. I think of Thrawn as a flawless tactician, who had a deep understanding of technology, and how to utilise it in ways that others cannot comprehend, and the best strategist in the galaxy, but not flawless.
Keep in mind, outside of their own geniuses, the commanders of the New Republic were trained. in relatively, the same way, likewise with the Imperial commanders. There always was a "standardized military doctrine". This is why I found the introduction of Garm Bel Iblis as a foil for Thrawn appropriate, he was fighting the war his own way, with his methodology, which produced innovations(a-wing slash) that Thrawn couldnt have anticipated, since Bel Iblis operated outside the NR military doctrine.
Yes the 10 steps ahead was a bit of a stretch, but you have to admit, Thrawn completely dominated most NR forces utterly. As a story telling mechanic, it stressed that Thrawn wasnt going to be beaten via "by-the-book" commanders. He was probably 5-6 steps ahead in reality, but that doesnt quite have the same ring to it as 10 =3
As for the art thing, well I kind of believe it. There are always over-riding impulses that are ingrained deeply into individuals, fight or flight, the urge to breed(giggity). Individuality is always present, but there is always a unity behind a culture whether it is genetically ingrained or socially trained from birth. Thrawn simply saw those impulses, and manipulated it to his advantage