In my mind, perhaps pay2win is another way of starting a pnp campaign with high level characters but never having played those characters up the leveling process. In DDO, you can, to an extent, buy items or features to do this. I have always preferred a smell the roses approach to DDO and enjoy the levelling process but I realize others only want to play end game and pass levels as quickly as possible.
That is fine, I get it, different strokes for different folks.
That being said, the DDO store has been, in my mind, on a slippery slope / pay2win course in another fashion. My fear was, and is, that as new content comes out, the new content will become harder and harder because it is built around the maximum you can be using Store resources, not the minimum, thus requiring you to buy from the Store to succeed, particularly if you are a casual player. Even though there MAY be options in game to bypass the Store, the reasonableness (or horrid drop rate of grinding) make it so that the only "real" option is to skip content, not play, or pay.
This can mean requiring you to TR, perhaps multiple times, or if you choose not to TR, to carry store bought items, like pots, and other various and sundry items to complete questing, especially at higher levels. Or perhaps, you just avoid content, like raids, because of the intimidation factor of not being geared out.
My original hope was that the store would focus on non-game affecting items. Cosmetic items - like armor, hair dyes, etc. While they have done some of that, the price points, imo, have created underwhelming revenue. Rather than revamp them though, DDO instead began walking the slope of putting more and more game affecting items in the Store - items players now take for granted but weren't there at the start but have been incrementally added: pots, +2, tomes, +3 tomes, elemental weapons, shroud ingredients etc. The idea of the slope is you do not notice how far you have gone until you are at the bottom.
In my mind, DDO is fun, and I really do not care about other players paying money to get to various game points that they enjoy. What I do care about is that DDO continues to make content built around certain assumptions of power gamers that in turn require casual gamers to use the Store. That slippery slope creep is there, imo. Power gamers do not have this problem - they have the time. Casual gamers do not.