It's very clever on SEs part.

They can't sell gill without killing the economy, so they add an item people can trade for gill cutting into the RMT profits.

It's no more pay to win than it was before though, people always had the option of increasing their Gil by paying an RMT.

I've always considered pay 2 win games to be ones which sell better gear in the shop than you can get in game, that's just me though