Hopefully this shows others that you can make successful games without pay to win mechanics.
https://variety.com/2018/gaming/news/candy-crush-saga-1-bill...
See Jarwain's comment in a sister thread.
As for runes, IIRC you couldn't buy them with the paid currency, Only with the currency earned from playing. It's a moot point since they merged runes and masteries anyways.
You don't have the same pool of characters as other players who've chosen to pay for their favorite champions and this is clearly a disadvantage.
This is different from games like, say, Overwatch, where the entire hero pool is available to everyone (different game, sure but the point stands).
Firstly, stock weapons are typically the strongest among each class.
Secondly, you can get every item in the game without spending a dime via one of the following: 1) the drop system, 2) the crafting system, or 3) trading.
While this is partially true, there's also a large set of items that are straight upgrades especially in competitive. The Cruisader's Crossbow, Ubersaw, Escape Plan and Gunboats are just a few examples of completely superior weapons and while their usage in casual isn't as wide spread you'd be hard pressed to find to find a serious competitive match where these aren't all being preferred.
There are also an assortment of weapons that are banned by competitive leagues because they practically break 6v6 gameplay. A good example is the wrangler + Rescue Ranger combo. With a good engineer it makes it practically impossible to kill a sentry.
I still agree with you that this doesn't make TF2 PTW for the other reasons you've listed, but it's occasionally been a problem in competitive when players don't have the "required" unlocks or the item servers are down.
Overwatch also has zero pay-to-win mechanics.