What if we normalize champions' powercurves?

I've always wondered why certain champions are so geared towards the early game, midgame, or lategame. Entire strategies can be geared towards ending early or turtling up until full build, all based around what champions are strong when. Our team has shaco, they have vayne? Better hurry up and end, despite the fact that right now we're having a nicely matched game. Generally the utility-based champions are way too strong early and the damage carries are way too strong late. The COTC nerfs and the adc QQ threads, and the late game tank QQ threads show you that.

To my understanding there are only a few factors that make each champion's powercurve different.

1. Base kit. Some champions become very strong at levels 2, 3, and 6, simply because their abilities are strong and independent of items. Lee sin, Xin Xao, and Shaco come to mind (huh, they're all junglers). Xin becomes very strong because he becomes a 1v1 monster early on with his strong dueling kit. Lee and shaco have a lot of utility tied to their abilities combined with high base damages, making their ganks effective.
2. Item scaling. Some champions become extremely strong when they get a lot of gold because their kit synergizes so well with bonus stats or item passives/actives. This is most adc's, and anyone defined as a "hypercarry."
3. Powerspikes. This is unavoidable, but things like completing triforce or finally getting bf sword, or maxing a certain ability all affect a champion's relative power. Certain item trees and skill max orders are better than others to tune this, but it's not an easy lever to use.

Mostly the first two items on that list are used as balance levers to champions. I personally wonder why Riot doesn't use them to tune champions to make each champion (roughly) equally useful at all stages of the game. Do you think Riot should do that? I personally hate hearing that one champion will be strong or weak at a certain stage of the game simply because that's how they're designed, and there's nothing you can do about it.

Now, you may say that damage has to heavily outscale defenses and tanks have to be weak lategame, but let's look at why. Damage has to win in the end because it is what takes objectives and wins the game, but this argument is used to say that late game carries should always kill tanks. Imagine what would happen if damage did not outscale defenses. Your team wins the fight, kills all their team except the enemy supertank, he ran away low after the carries died. What's he gonna do to protect his towers? Stand in front of it and lose what little is left of his health to prevent it from taking damage? Clear your minion wave to make you have to tank the tower shots? No, he can't do either of those without damage. Also, if the enemy carries are too slippery, you can still use baron to force them to fight at their towers as you whittle them down.

I also think that normalizing the powercurves would help people enjoy the game more. The best games last the longest and don't lose their fun teamfights just because the carries reached full build. The early game adc's would be less salty that they can't do much at that stage of the game, might blame their supports a bit less. Same with the Lee's and Shacos that nag their teammates for not killing the nexus at 20 min. Also, games would be more predictable. There are 130 something champions in the game and remembering their best uses is enough to think about; memorizing their powercurves is just brainstrain.

I propose that Riot makes these changes.

1. Reduce base utility, tankiness, and damage of "early game champions," compensate with better scaling. This will not only shift Lee Sin's power from early to the entire game, but will reduce the damage that tanks do. They will be more likely to buy an offensive item because they will scale better with those stats than they do currently, but 1 offensive item and 5 defensive items will leave them about as tanky and damagy as before (just with better options). Skip to 3 for why.
2. Increase the bases and cut the scaling of current hypercarries. ADC's (and other late game champs) will be stronger in the early game than they currently are, but will not become late game monsters.
3. Increase the cost and stats of defensive items, so tanks can still be useful in the lategame, but will be relatively unaffected in the midgame. They would be slightly weaker in the early-mid game, before they complete their first 2 items.
4. Tune items that scale with defensive stats and base stats, such as Iceborn Gauntlet and Last Whisper, because they will be too strong in late game with tanks' increased stats.

I know this is kind of a low-elo view, but would you enjoy the game more if your strategy wasn't determined by the clock?