He can keep bashing Hiruzen because, yes his feats so far is not taking anyone stronger in part 2. Yes it is true nobody at that time was going to see Oro because many lack battle experience to take Oro on at that time.
IT is different now they aleast stand a chance with more battle they gain and experience but back then they stood no chance. Hiruzen next kage would have been Oro, Jman or Tsunade but they scattered. So he gave the tittle to the next generation after them. After that next generation guy died. He had to re take it and back then Kakisha, gai or anyone else was not ready or did not have the battle skills to take Oro out. Now many people could aleast work together or one could maybe aleast battle on par with Oro.
But it funny no one in the village.... Lmao he did not even think about Danzo lmao.
Also still Hiruzen by hype

(You know what I am going to say)