You and Stonewall and even Riot have a very blind view on this and how it should be handled.
Fervor of Battle is basically just 80 free AD that only counts on auto attacks (does not scale with abilities)
If the mastery is too strong it makes auto attack champions as a whole strong, specifically those that can easily keep it stacked.
However there are things to consider here
If Fervor of Battle is the best Keystone, perhaps the problem isn't Fervor of Battle. but rather the other Keystones. The idea that something is strong and must be nerfed is really awful, it has resulted in a lot of champions being absolute garbage because of being over nerfed (See Kha'Zix and Sejuani) The crit mastery benefits a small minority and for anyone but Yasuo/Tryndamere it is a mid/late game mastery, taking it against early game focus will hurt you a ton. The Death Fire mastery is trash, it is strong on like 2 champions, and those champions were already pretty BS to begin with, it just contributes to champs that already have harsh DoTs. Movement Speed after damage is bad on everyone but Hecarim who is pretty shit this patch and about to get nerfed further (or did that happen already) Thunderlords is decent, Wind Speakers is okay, Grasp of the Undying is decent, and then the other two if defense tree are garbage, the stacking hp one doesn't stack high enough to be worth taking unless there is no other options (It's not that Undying Grasp is too good, it's that it doesn't suck) and the % damage one is tiny, you reduce an outrageously small amount of damage and it makes you take allies damage when they play bad. The concept is awful but even the few who would use it, are getting more out of the first 5 points in resolve (6% armor/MR) than they are out of the 2%.
The other thing to consider is that the community has no idea what they are talking about. We say "Fervor OP" but lets quote a few things from stonewall
- Trundle is strong due to Fervor of Battle
- Trundle is an early game champion
- Bites hurt a lot
Trundle is not specifically strong due to Fervor of Battle, what I mean is other champions can use it too, and nothing about Trundle makes his usuage of it better than other champions other than the fact that he is perceived as a better champ by some people.
Trundle is an early game champion, Fervor is a late game mastery, it does help early to, but the gains on it are small. At the times Stonewall did his first two ganks, assuming Fervor Math gives you the same increase per level. His 10 stacked Fervor would give him 13 damage on the first one and 22 on the second one, Now to make that even worse, he didn't have full stacks, With his final attack on his second gank, he had 5 stacks of Fervor, giving him 11 bonus damage, basically a longsword. He didn't win this game in any way because of Fervor, but rather because he snowballed early and effectively, Fervor doesn't snowball you easier.
Trundles Q does 100 additional damage +20% of AD, it does not benefit from Fervor of Battle, (I mean since it's an auto the auto attack will, but only as much as any other auto attack) His trundle Q does as much damage as it does because it's meant to do that, and even then it didn't do that much IIRC.
Trundle is strong either because he's been strong, and there is nothing wrong with being strong, if you're not strong, you're weak and Riot should not be looking to make every champion weak, we already have 1 Skarner, we don't need 129 more. Making sure something is not overpowered is important, but denying a champion from being strong, especially if it's just in the meta is dumb. Riot should not give a shit about the meta, the job of one who aims for balance is to make sure that everything is fair, that's what balance is, equality, fairness, it's 10 pounds on one side of a scale and 10 on the other. If you're basically Skarner, so weak that you can't stand, you're not balanced, if you're Yasuo and having an easy time being oppressive and strong at all points in the game while being extremely hard for the enemy to survive 1v1, then you're not balanced. For everything positive there must be something negative. (that doesn't mean give MF a damage passive and then take a shit on her base AD) Everything should have some sort of cost equal to benefits it gives.
That's one of the 3 biggest problems with Riot balancing, I'll say all 3 of them though.
- There are multiple kinds of costs, effort, mana, cool downs, stats, and for LoL specifically, points of weakness. Riot doesn't understand any of this, or the importance of costs.
- Riot isn't actually aiming for balance, but rather an idea they each individually have for the game, despite collaborating to create it, it'll never be what any of them wants it to be.
- When something is strong or even just meta, Riot immediately looks to nerfs, no buffs to other things, they never consider that maybe ______ is strong because something else is shit. They think they're close but they don't even know what to and so they just nerf until everything is even. Imagine it like trying to pound the earth flat so no spot is more elevated than another, but you're unwilling to add dirty to a hole, every time you discover or create a new whole, you must pound the entire earth down further. It'll never work out for you.
Well that's the end of that wall of text, thanks for reading I guess.
, and forced any adc into rushing crit for sustain (nerfed now)
now
(doesn't feel problematic right now during the bad itematisation but could be a problem in the future)
with 
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