He did beat Hiruzen and his failure with RDS has been rectified.
I don't think he cares lol
His arms were useless, give him a break
And Kyuubi Naruto did nothing impressive against him. Orochimaru was extremely impressive in that fight, being able to fight on par with that rage demon while sick and weakened and dying.
Sasuke and Itachi, failed there
Ryuchidō, failed there
Successes include
Forming a cult-like following
Creating his own mock Sage Mode through Curse Marks
Evading Konoha for years
Evading Akatsuki for years
Evading Suna for years
Experimenting his own body to become extremely, extremely resilient
Deciphering the Uchiha Stone Tablet without the Sharingan
Winning Part 1
Bypassing Totsuka Blade
Assassinating and impersonating the 4th Kazekage for who knows how long
And being the only character to create his own dimension...
But whatever.