Orochimaru on par with madara
Orochimaru has his jutsu ability back and we all know how powerful and manageable Oro is with his wide specter of alternatives of jutsus and his long fighting experience. He even got senju DNA, thus making it theoretically possible for him to use mokuton as shown with Obito. He who has studied Hashi etc, would have some knowledge about some stuff surrounding that topic. This would make Oro much stronger.
- Regneration abilities
- Defence abilities, take rashomon in notice
- His speed and reactions, clearly shown against the fight with Naruto
- Powerful ninjutsu and taijutsu
- His summonings, he has also many choices, just like Jiraya(Kishi has clearly made Manda look weak, but in reality he was a monster, but hes dead so yeah..)
- Wide specter of methods to attack and stabilizing his senses to fight properly against strong foes
- His sage art, he clearly has senjutsu (Kabutos marks was a hint, and also tsunade/Jiraya had it)
- His ability to not be able to die, give a new form. (Sasukes murder plan was an exception, Oro was at his weakest, not able to use any ninjutsu either)
- Knowing almost every jutsu there is
I find it time consuming showing proof of this just to satisfy the uncertainty of this thought, however me as a fan and lover of the Naruto series should by now know the power Oro hold, his abilities and capacities. It has been shown many times, yet everyone should be aware of it.
I think we have been ignorant to the fact that Oro is a great shinobi. Just to add that also Kishi has decreased his worth as a shinobi and significance, also his usefulness; not using him as a fighter. Maybe he has something in hold, knowin Oro.. So just to conclude, Oro can fight on par with Madara, or he can last at least a little longer than Sassske and naarotoo. just an assumption