I didn't mean for her to level up exactly like Sauron, merely that it feels off to me to have her gaining levels by killing enemy units instead of acting to protect her people and realm (and not by just killing them...). I would like to see her made into a far, far less offensive unit, one that you just bring in to destroy buildings, not to kill hundreds of units. Maybe give her basically no base attack, instead let her have a magical shield that repels and knocks down enemy units. Give her a healing spell like the old samesingers, and have her level by granting her blessing and gifts on units, heroes and buildings. I realize she would be a force to reckon with on the battlefield if she chose to take up a sword and fight, but that doesn't fit her actions of mainly being a passive protector, her only real offensive action was to destroy Dol Guldur, and even then I don't think we should imagine that she was storming the stronghold like she does in the movies, barefoot and unarmed.
You might disagree and still want offensive Galadriel, but I just feel like it is contrary to how tolkien has written her, not as a great warrior, but as a great protector.
The gameplay-related points I remarked in my previous comments exactly explain why it wouldn't be wise 'relegating' and binding Galadriel to a so strict supportive role, inevitably colliding with her status as the most powerful hero of the faction.
Her attack is meant to represent a widespread spell that obviously involves more than one unit; being it a very particular and unique type of attack among the other Elven Heroes, I really think that it's instead very suitable for her.
If you are a bit concerned about Galadriel picking open fights like a 'regular offensive' hero, then you should consider that this issue was solved in the Edain Mod 4.0, as in the 3.8.1 version she indeed seemed a bit out of place with her problematic role as a sort of tank (attacking directly) with mainly supportive abilities.
So, a less offensive role wouldn't have so much sense, as Galadriel already is a mainly supportive hero.
Some of your suggestions (like the magical shield) could bring things to the extreme side, like a very strict and imperative defensive role (that Galadriel doesn't need at all).
And, now, the cherry on top of the cake.
Those statements about Galadriel's role in the War of the Ring and her act towards Dol Guldur have really been a direct wound to me
Galadriel was anything but 'passive' during the War of the Ring.
In the books you will find many passages that clearly state that without her personal presence and powers Lothlórien would have ineluctably fallen either by the Enemy or the Time.
Tolkien specifically tells us that it was due to the power of Nenya (therefore Galadriel) that the three assaults against Lórien were repulsed, although the Galadhrim indeed fought bravely for their land.
You should always consider that the 'general mechanics' (War, defence, ruling, power) of enchanted kingdoms as Lothlórien are definitely different from the common (mainly human) kingdoms', since they greatly differ in Nature.
A similar thing can be applied also for her actions in Dol Guldur, not only significant for the War, but also symbolic as they resembled what Lúthien did in the First Age with another fortress of Sauron.
Galadriel should indeed be pictured walking barefoot and 'unarmed' while she storms that place with many possible varieties of destructive powers like shockwaves, dreadful weather-related phenomena, gates and walls crumbling at her presence or a mix of all these things, easily justified by what we know about this more-than-8000-year-old Noldorin Princess from Immortal Lands.
And, remember, Dol Guldur is an enchanted place, permeated by the dark power of Sauron.
Magic can most of the times be effectively countered only by Magic as well
This is a recurrent theme in the Tolkien's writings.