Im not sure if you're trolling or literally that stupid. The more I read your posts, the more i get convinced that you're absolutely clueless about the champ.
Let's start from a comparison. What differeniate mages from assasins?
Mages usually got more aoe, got more cc and usually immobile and ranged. Examples: malz, zyra, brand, etc.
On the other hand assasins are usually characterized with high mobility, high single target damage(doesn't mean they don't have aoe abilities) and have to get "in personal" to deal their damage. Examples: fizz, talon, katarina, zed, etc.
Now let's talk about leblanc, and what makes her good. Well to start off, she's the only ranged assasin in the game. Range is a big advantage and it seem not fair that a ranged champion can do such high burst and be "safe". This argument isn't entirely true, since she's played like any other assasin in the game. She need to get "in personal" range to maximize her damage. "but she can go in and immidiately get out so she's still out of reach". This is partly true, but being ranged got disadvantages too. Surprise! Ranged champions are squshier by default since they aren't getting magic resist per level. Leblanc also doesn't have any sustain either, so she's probably the most fragile assasin in the game.
Now what's wrong with your suggestion?
To begin with, it seems like you completely clueless about how her kit works by stating that her distortion isn't part of her damage combo. Distortion is the ability that allows her to act like an assasin by going in close range. Any combo that starts with W to close the gap, effectively minimize her burst. Any single combo you gave makes her be played like a poke mage, which is only effective if she's already extremely ahead.
Another point is her distortion damage is already lower that her single target spells, and the damage is relatively average to allow her wave clear, so lowering it even more just gonna make her shit tier. Story time! About 2 years ago LeBlanc's kit was more focused around her single target burst, specifically around her q r combo. Her burst was much higher, but she lacked any wave clear and fell off late game since of how single target oriented her kit was. With the changes they rebalanced her kit around her w, while reducing her W Q R damage because it was much more abusive and frustrating to play against. So you pretty much suggesting to bring this playstyle back.
You bringing examples of champions that got nothing in common with leblanc. Diana is a melee ap fighter, with a shield that allows her last in a fight. Both kha and tristana had resets on their mobility moves which potentially can do x4 the damage within a really short time window, so those abilities are made specifically for mobility instead of damage to support the "in and out" pattern, not to mention those champions are ad and doing much more damage with auto attacks.
The only ability you can potentially compare leblanc's w to is fizz's e, which does more damage, got lower cd, and applies a massive slow.
You think you're right, but it doesnt mean anyone have to agree with you, actually most doesn't, since you suggest straight nerfs without any arguments to support it except of your biased opinion. Most haters just gonna look at champion's strengths while being completely blind to the weaknesses. Leblanc might be not the most fun champion to play against, but if you break down her kit to the components, and analyze her kit as whole, its pretty simple to figure out why it works the way it is. You can disagree with me as much as you want, but that's how it is. And if the balance team doesn't adress her balance state for such a long time, it seems that she's not that big of an issue as people make her to be.