Note: None of this is meant as an undermine of what you're saying, it's to provide context and hard facts and numbers behind the statement you didn't seem to like much.
That was a nice explanation. To clarify, I was never taking issue with your initial claim. I just wanted to clarify that the fluctuating experience group is one of the strongest exp groups because it takes relatively low experience to level up for most of the game.
https://bulbapedia.bulbagarden.net/wiki/File:ExpToLevelCubed.png
I think that this graph is the best for illustrating my point (which you supported with your explanation).
This list not designed around speedruns, as stated in the OP. A speedrun list will always end up heavily weighted towards earlygame mons, soloing, and techniques you would not expect a player to understand and execute (for example, spinner manipulation). It's not particularly intuitive to most players to avoid as many trainers as possible, skip any and all items that aren't completely necessary, and muscle through every poor matchup with X items.
Sorry, I was too brief in my post last night. I do speed run drafts where each player picks 3 pokemon (snake draft style) and races to the finish. The team must always stay within 5 levels of each other. For instance, I might first pick Ralts and second pick Numel (starters are free) and race to the end with 3 pokemon that finish around level 47. This is effectively what is being tiered here, since we're shooting for the most efficient route with a team of multiple pokemon.
I strongly disagree with your claim, "It's not particularly intuitive to most players to ... muscle through every poor matchup with X items."
If we're ignoring ways to play more optimally because they "aren't particularly intuitive," we might as well put Regice in F tier, because it's awfully less intuitive to catch Regis than it is to figure out that using calm mind to start a battle is an effective strategy.
This isn't relevent to any of my arguments about why pokemon should move; it's a disagreement with the ideology of this list. Gardevoir's strength after 2-3 calm minds, for instance, ought to be considered when ranking her.
Chimecho’s got 3 major flaws.
I agree with all of these flaws. But look at Snorunt, sitting in E tier! Snorunt requires Shoal cave (a completely optional area) be at low tide. You have to navigate the entire cave and find one with a 10% spawn rate, and it comes at the same level as Chimecho! Chimecho came a whole gym earlier and has much better stats than snorunt. Snorunt has to wait until level 42 to become useful. Chimecho also has better coverage and a better experience group.
Ultimately the difference between E and F doesnt matter much, but some pokemon in F are definitely more useful than pokemon in E. Either Snorunt should move down or Chimecho up, probably both.
And a reminder that Lileep should move from D to E, because that seems to have been overlooked in the past few comments.