Saurons forms is an unfinished feature by the former lead dev who unfortunately left. We will have see how we can finish this in a reasonable way. You do get a major buff for having the ring though.

If you wanted to go by the lore, Sauron only ever needed the ring to fully regain his power (keeping in mind that he was still more than capable of causing serious problems for everyone without it) and it had nothing to do with his form, you could just remove that whole thing and just give the buff for recovering the ring.

引用自 Talyc Verda：

If you wanted to go by the lore, Sauron only ever needed the ring to fully regain his power (keeping in mind that he was still more than capable of causing serious problems for everyone without it) and it had nothing to do with his form, you could just remove that whole thing and just give the buff for recovering the ring.

True. The no corporal form of Sauron is a fail of the movies (in deed, Jackson filmed a scene where Aragorn fought Sauron, but he removed it from the movie).

By now this is already implemented. Sauron can only regain his form by gaining the ring. No in between anymore