Depending on what people call p2w, some may say that this game has been p2w pretty much since it launched, some may say it's pay to get there faster. Some believe p2w is limited solely to gear that absolutely cannot be obtained through playing the game, and is stronger than what f2p's can get. Others think any kind of gear obtained or facilitated through real money is already p2w, regardless of it's availability to f2p's.
Now, all or almost all MMOS currently around have a pay to speed up model. BnS is no exception. Problem is that things reach a border line when the f2p's grinding behind without paying can't hit the gear cap in time before a new set of gear becomes available, or when things, like this very event, happen before they do, leaving only those who pay (or the scant few that went way above to the point of playing countless hours, or those super talented individuals that can do a lot more with less) to benefit from it all. I think this is indeed as bad as plain p2w. Aside from this event, is BnS reaching this point? I'd have to sit down and study it to know.
As for this event, considering the opinions, it does seem as a slap in the face to players who are not paying for their gear, simply because many of them didn't have enough time to gear up for it. The event itself is not bad. It simply requires maxed or near maxed gear, which would have been enjoyed by more players if they had the time to reach the gear caps. Maybe if the event was made late in the life of the current gear line, and started when NC felt enough f2p's had the gear needed for it, there wouldn't be so many complaints.
I cannot do the event, so i'm speaking from an observer's point of view. Also, as always, these are my humble opinions.