I do not see a problem with some heroes being better than others if the circumstances of their encounter changes. Twisted Treeline isn't balanced for every hero, but it is not exactly a mystery and if you care about Twisted Treeline you are already ready to pick Mundo or the other 1/3 of the heroes that are TT viable. If Teemo and Heimerdinger become the God Kings of Dominion, it will mean that... people play Heimerdinger again. If this upsets you, the default map will prrrrobably be left in the game.
If Teemo and Heimerdinger teams become hard comps to face, people will pick up counter comps that kick Heimerdinger and Teemo in the dick. The circle of life continues.
Moving on, Kayle's "buff" actually significantly nerfed her. Also, Co-Op vs AI mode is for farming your daily IP, farming IP as you level, and trying crazy stupid shit out. The second you recognize the AI quirks of the bots they cease to have any difficulty or meaning. You will also be leveling for awhile Zed, so you may develop mistaken notions of what is "crippled" and what is "hella crunk." Basically it is cool to play whoever you want until things become so serious you begin to reconsider, and even then, you can do whatever the fuck you want in Solo Queue Unranked at Level 30. Just be prepared for the consequences, but yes you can out-skill solo queue with a "bad" hero.
Before: Kayle needs items to scale, but she scales ridiculously well. Her passive is the best in the game, as though they realized she could not actually exist without having the best passive in the game. A strange balance, but strange fits an esoteric off-pick well.
After: Pretty much the worst passive in the game. Loss of her old passive demolishes her old effective builds. You are expected to take advantage of like a 1:1 AP ratio on Reckoning.... but her new effective default build is supposed to be an "Auto-Attack Steroid Popper" with Malady and Madred's. Not only does Teemo do it significantly better, but good luck buying a nice AP item when you are looking at thousands of gold for an effective offense(Malady -> Rageblade, Rageblade -> Madred's, etc, not even counting that you are ignoring defensive items on one of the glassiest glass heroes in the game.)
The problem is that Kayle is now some sort of really terrible Support without the muscle of serious support(Taric heals, Sona everything, Janna shields, etc), the leeway or even ability to farm effectively to assume her now even grosser need for raw gold and items, and she scales worse in the end-game if she actually gets those items. Don't forget that Kyle ideally wants enough CDR for Righteous Fury to be near-permanent use. Malady, Rageblade and Madred's do not give CDR. Welp.
For reference, 10% of 200 MR/Armor is 20 MR or Armor. I think it got upped recently to like 15%. So.. 30. Kayle's passive is only significant against enemies you should not focus(first.) If you stack it on some ranged AD carry with 60 MR, your Malady will remove 24 MR and I guess your Passive will account for.. uh... 6-8 MR? I guess on average Kayle's passive will account for like 1/5th of a Malady and some other depressing fraction of a Black Cleaver. Compare this to Teemo's poison, Vayne's quicksilver, Twitch's passive(admittedly, playing Twitch these days...) or something more practical for a fast attacker(Yi, Xin Zhao, Jax... all more practical.) It's just basically the most disgustingly bad passive I've seen in a long time and that is competing with shit like Kog'Maw.
Imagine if Kayle's passive was just a flat stacking amount. 3 Armor/MR. At low levels this would be an insanely powerful chunk of defenses removed and a Kayle/Massive Aggressor Lane would be terrifying. All she has to do is pop Righteous Fury and get in 2-4 hits and you're ripe while Xin goes to town or something. Adjusted for level scaling at a fine pick, Kayle might be more worthwhile as an actual damage dealer(Malady -> Black Cleaver?), able to bust tanks and tanky DPS like nobody's business. As it is currently, if Kayle actually stops to fight somebody she will lose. Even in that fantasy world we go back to where they didn't just zone you out of your lane.
In all fairness Kayle's ult is really fantastic if you are Light Yagami. But Teemo is a better annoying little asshole buddy and Zilean is a better support with a better ult. Kayle is good if you plan a comp/lane around it, otherwise you will be zoned hard and expected to make 2,000 gold before you're actually allowed to deal damage.
Man, at least give Righteous Fury a passive when it isn't toggled on.
