'By the way', you're wrong there because Gandalf was bound not to directly oppose Sauron's power with power (not just
his power, just 'power'). He was there to provide the Free Peoples with counsel and to help them unite against Sauron, not to do the fighting for them. And in any case, as I said
the Three Rings were not made as weapons. Here's what Elrond had to say about them:
'...they were not made as weapons of war or conquest: that is not their power. Those who made them did not desire strength or dominion or hoarded wealth, but understanding, making, and healing, to preserve all things unstained.'
- FOTR, 'The Council of Elrond'
If Gandalf and the others hadn't been bound to appear humbly and not to use their power offensively then they could have appeared openly 'in forms of power and majesty' and confronted Sauron directly. The time for such open intervention by the Valar had long since passed. (And besides, such a confrontation would have been appallingly destructive).