Care to elaborate on this a little bit? I'm all for appreciating the arts, but in my experience no one has given me sagely advice along the lines of "Study great works of art, you'll learn to better perceive the flow of battles."
Thrawn also studied art. Something that would lead to his victories in his final campaign. His study of art allowed him to see the weaknesses of his enemies and exploit them. While he was an incredible tactician, this method proved successful countless times during his final campaign.
This sounds like Thrawn had a weakness for over-thinking his plans. Complex plans are generally bad ones, especially on the battlefield. Envisioning the path to Galactic dominance and actually achieving it are worlds apart.
He also had an incredible attention to detail. He would collect seemingly insignificant pieces of data that would prove to be invaluable. He had collected a near encyclopedic amount of data that gave him a sense of omniscience. However, this led to a couple of defeats when he assumed that his enemies knew more than they actually did.
Thrawn was also a great planner, laying out complex plans that allowed him to literally stay one step ahead of his enemies. While his enemies were still trying to figure out what exactly he was up to, he had already moved on to the next phase of his campaign. During his final campaign, Thrawn had laid out the path to victory. If not for his Noghri bodyguard, his plans would have come to fruition and he would have taken control of the galaxy.
Nonetheless, interesting character. It's great to see some military commanders being shown as competent, and it's also refreshing to see some good military action.