I'm forced to reach that conclusion : Galadriel with the One Ring is quite awful.
Why ? I realized it some time ago but even more with the Tranduil's Halls horde map. She is clearly better there if she doesn't pick up the One Ring.
It is all the more clear now that I saw that Tauriel's level 10 triggers Galadriel Queen of Twilight even though it is not mentionned in her level 10 description that points out at a quite poort ability otherwise (Ha, ha, Edain team I love your jokes

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But the main problem with giving her the Ring is that without the Ring, she can benefit from two roasters of wonderful abilities, 2 forms with abilities independant with each other and this is even better : if you use all Galadriel's abilities, then turn her as Queen of Twilight, then when she returns at her normal form, she gets all her abilities refreshed !
That is why I say this is even better than tow forms with abilities independant with each other, because one form refresh the other one !
When she get the Ring however, she is blocked in one form, perhaps powerful, but nonetheless she is blocked. She can refresh abilities of others but herself cannot improve her own's timer, therefore as lady of Light, she has not that much occasion to trigger her leadership, a leadership that is moreover very limited in time and in space.
in comparison, I recall Saruman the Blessed gives all units twice damage, twice armor and twice experience indefinitely to all units around him

As Queen of Twilight, she is quite better, but once more blocked in her form and has to wait for her abilities to be refreshed. In a hard battle in a precise moment, there is not a better way to deal with it than having Galadriel without the One Ring, use her abilities, give her the Queen of Twilight spellbook, and afterwards, reuse all her standard abilities.
In the Thranduil's Halls horde map that gave me so much problems, I now have found the solution : give Tauriel her gift, trigger her level 10 then get the Queen of Twilight, afterwards refresh Tauriel's abilities, use Galadriel others abilities, reuse Tauriel level 10, and so forth...
With the Ring, it will only spawn a tornado that is powerful but not as quite as the benefit given if Galadriel has not the Ring. Those powers should be more significant if Galadriel has already a Ring form.
My suggestion is that :
-Vigilot's timer should be as long as the standard timer on Galadriel's Lady of Light, for not lacking power in comparison with the standard use of the Spell.
-If Galadriel without the Ring use Queen of Twilight, at the end of the effect, when she returns as Galadriel, all her abilities should not be refreshed, but rather reseted, or at least put back at their last state
-If the use of "Queen of Twilight" powers triggers a tornado, double at the very least the speed of that tornado, make it feel more powerful, it would be so fun, and also the use of that power would refresh all her abilities as Lady of Light, to make it the contrary of what is done now, making the use of the Ring far more enjoyable and interesting.