Tf2 is somewhat pay to win. You can buy additional weapons with different stats or abilities.

Sounds like you haven’t played it much.

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.

> Firstly, stock weapons are typically the strongest among each class.

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.

I have about 250 hours in it, but I stopped playing in 2013. At the time, I found the drop system to be pretty unrewarding unless you paid for keys (or just bought what you want). Has it changed since then?

Yes, it has changed a lot since then. Most significantly, Valve did a ton of re-balancing, making stock weapons even more viable in regular play.

Not sure where I mentioned it being pay-to-win? I put ~1500 hours into TF2...