Excellent and important discussion!
My humble 2cents:
As a player that will likely spend real cash, i do think that whatever you can buy with cash, you should be able to get with additional effort, for free - it will defeat the F2P essence if its not like this, and might drive away players that otherwise get a job in the meantime and start spending cash.
This said, "Pay to win" becomes sort of moot point, as me, playing an hour a day, but spending cash, might likely not have a bigger advantage than someone that plays 4 hours a day, in my opinion - sure, there will be the odd player that plays 10 hours a day AND spends money, but those should be rarer.
Essencially, real money should be a way of getting things faster.
I do exclude everything cosmetic related (paint jobs, hula girls for my cockpit, etc.) - those should be IRL cash only - they dont unbalance the game, no player that plays for free will necessarely be left underpowered, but these things will sort of create an aspirational desire to spend money: Someone might not be thinking of spending any money, but perhaps after i blow them away with my garish pink atlas, they will reconsider