Outside of some blatantly OP champions and some that you specifically want nerfed, it really sounds to me like you're fine with the game. That's cool, but many high elo streamers and a lot of the community are very vocal about what they don't like about this game and this game isn't just for you to play.
Why? It's not even that strong. I wish more people rushed it, because it's so god awful that they essentially wasted their gold until they get more items.
This is just your opinion. The ultimate passive has been problematic on many bruisers since it was still on essence reaver. But you specifically have no problem with it so it's ok. I got you.
Already exists though. Bruiser items have offensive stats on them. Tank items are more heavy on Resists than pure HP and Juggernauts are nothing else than a mix of the two.
A lot of the juggernaut items are simply more effective on bruisers. Lots of people have been on record talking about this.
Diversify Mage itemization. All just rush magic pen and grievous wounds.
Rework ADC items all just buy life steal and crit.
Reduce the overall gold income available.
Wouldn't fix anything but artificially draw out games. Nobody wants to lane until 20 minutes.
Reduce damage across the board by 10%.
Wouldn't fix anything, besides potentially just making tanks or bruisers OP thanks to how damage vs defenses scale.
I see you can put words in my mouth, excellent job. At least tanks would be more prevalent in the game and have a real place in the top lane again. Perhaps games would last a little longer too.
They already exist. Runes as a whole are more gameplay focused than simply stacking your defenses up though.
So here is where your bias is showing itself. The runes are focused on doing damage. Stacking defenses up should be a viable strategy as well. Do you have any reason why it shouldn't be one? There's more than enough true damage to go around so why not?
Absolute bs idea. MMR is the bread and butter of the entire system, you cannot remove it and simply use arbitrary ranking like that. Would become entirely meaningless. If you're too ignorant to understand that divisons and MMR aren't the same thing and that you shouldn't complain about playing from a range of 2 to 3 divisions up and down you need to just shut up about this because you clearly haven't understood a single thing. Would also encourage people to play for KDA, which is a dogshit idea.
I played a ranked game last night. Nothing too special about it, won my lane and my game. But I checked my op.gg to get a full view of my opponents and how I performed against them. I had a Gold 3 jungler and the rest of us were mid Silver players. They had a Bronze 1 Ez playing ADC who was also first timing, but his MMR said that he was good enough to face and possibly beat mid silver players and a Gold 3 jungler. I wouldn't be surprised if our jungler sometimes went up against Plat players. This wasn't their game to win, and for no reason other than the matchmaking dealing them a shitty hand based on MMR. This isn't specific to me, people have had issues with the matchmaking that's even worse than the example I just gave. If you're completely ok with this, that says a lot about you and I don't think we need to proceed with this discussion further. Whatever changes that would take place would simply put people against someone with a rank similar to theirs or performance based on things like CS or average champion grade after games. And also, chill with the ad hominem attacks. It makes you look bitter and unintelligent. You're better than that.
Or you just change broken interactions but keep champions the way they are. This is why League isn't dead yet. There's always something new, even if you don't want to admit it. That's why balance changes are made. Many champs have clear cut weaknesses and those that don't really have any obvious ones are generally kept weaker because of it.
No, there are some champions released that are blatantly overloaded and they're nerfed into obscurity due to that. It's also no secret that Leagues player base has begun to decline due to their balance decisions. Vayne is supposed to be weak in lane, but they buffed her Q cooldown to give her better lane presence, and later buffed her ult on top of it. The reworked Irelia was nerfed less than 24 hours after her live release. Aatrox was also nerfed into obscurity post-rework cause he was too strong and they're just now touching him again. These champions are clearly designed with strengths at the forefront and whoever is calling the shots with the balancing clearly has bias, which is why Riven and Vayne are still broken after all of these patches.