um...oro was the most talented of the 3, thats why he was the 3rd's favorite, oro said itachi is stronger than him, so how can tsunade be stronger than itachi? itachi has been the strongest character introduced so far so i doubt she is stronger than him.
You don't have to be the most talented to be considered the favorite, that's proven with Gai and Lee considering Neji is the most talented member of that team,but if Gai was Hokage no doubt in my mind that he would choose Lee to be his successor.