Doesn't GW2 sell gold and also better...dusting items or whatever? The thing that breaks down junk into useful junk.
GW2 sells a Gem currency (used in the shop), which can be traded for Gold. However, players can also use in-game Gold to trade for Gems... which gives the system a variable exchange rate. They also do sell rep boosters and various other baubles.
In the end, none of it messes with balance in any meaningful way, and I'm not seeing anything that Destiny is doing that messes with Balance in any meaningful way. People get caught up in "buying gear or weapons = p2w!" without realizing that P2W actually comes from the ability to buy better gear/weapons and then use them to keep other players down. That's not really possible in a Co-Op game. A game with Open PvP, Factional systems, etc.. then it's a problem.
If it's not keeping other players down and it's not an unavailable level of power without purchase.. it's not pay to win.. but like.. pay to equal? Pay to cut down grinding? Something like that.
Edit: I do feel I should state that taking a stance that it's morally questionable to sell any version of gear/weapons that could increase is understandable. I don't have a problem with it personally, and that's just me, but my point with this post was that it's not really a P2W situation.