What's the easiest way for me to explain my position here? Keep in mind, I am calm. If I was not, I would use all caps and likely break rules, so here you go haha.
1.) I have used most available Servants in the game through helpers/Friends.
2.) I noticed the following issues:
-Gil's attacks either do massive damage or next to none. This includes NP. Seems to be a Berserker and Archer Class issue, as even Cu Alter and the demon woman (name escapes me atm) have the same issue.
-My experience with Nero in BOTH forms has astounded me. Keep in mind, most people attack Nero, trash her, etc, when, from my experience, her NP does nearly max damage unless resisted, and even then, it does 40k on average plus effects. Not a single other Servant has come anywhere NEAR close to that level of power that I have used except Assassin Shuten Douji, Assassin EMIYA, Assassin JTR, Caster Nursery Rhyme, Rider Alexander, and Rider Francis Drake.
3.) I am quite far in the game, almost done with London, in fact, and this is why, especially after playing EXTRA and wrecking as her, that Nero deserves way more respect than she gets.
4.) Imperial Privilege. Enough said there.
5.) As for knowing what effects her NP has in terms of opponent parameters:
http://typemoon.wikia.com/wiki/Aestus_Domus_Aurea
6.) In addition to this info, remember, Moon Cell HGW is different to a standard one. In said Moon Cell, her NP is all but a real RM. It grants her extra skills, and all boosts and such to enemy parameters are rendered useless. She can REVIVE HERSELF. Last time I checked, not many Servants have that skill at all. Her NP would be higher in power rating if her Magus had a body. Remember, if she had been Kiritsugu's Saber, would anyone say she is beneath Arturia? No. From stuff I have read in the past, for an Alter to be created, the Heroic Spirit in question must have guilt, regret, fear and self hatred in some form. Does Nero have any of those issues? No. She accepts her past and moves forward with her head held high. Look at Arturia: Cold, distant, whiny, and wants to erase her past. Nero, like Alexander did, would dislike her for this reason alone.