Saruman's Ring

[Voralphion]

I think that Sauraman's ring was only an imitation of the one ring. Sauraman wanted to make himself great and powerful qand he thought that he would have the skill to create a ring that would rival the one ring and make him powerful. Unfortunately for him, he didn't have the skill to do so and the ring he made was only for show. In the introduction at the beginning of the book where Tolkien says that it is not an allegory of WWII, he says that if it was, Sauraman would've entered Barad-dur and found the information missing from his ring lore and made another ruling ring. This says that Sauraman lacked the knowledge to make a ring so the one he had was really only for show.
As for the istari's staffs, I think they used them to channel their power but they could still do things without them. The breaking of Sauraman's staff I think was symbollic of Sauraman's spirit being broken and him losing his power by wanting to dominate others. It also showed Sauraman that Gandalf would no longer put up with him being in charge of the order.