Board Thread:Wiki Discussions and Support/@comment-26152226-20150323185045/@comment-25632268-20150325092025

Didn't he explained what was with him and Uchihas during talk with Sasuke?

And about experiments - maybe Hiruzen didn't liked that side of his teacher and it was one of the reasons he chose Minato over Orochimaru for the Forth Hokage title. Oro as Hokage would not think twice before butchering prisoners for his experiments.