Eric Musco just posted on the official SWTOR forums regarding Season 5 PvP Win Trading. Apparently this practice saw a 90% decrease in win trading activity and 50% decrease in trolls.

Update on Win-Trading in Season 5 | 05.21.2015, 07:22 PM

Hey folks,

I am here to give an update on win-trading and ranked “trolls” for Season 5. As of earlier this week we sent out another round of warnings and action against players who were participating in win-trading or being trolly in ranked play. I did want to provide some additional information besides just letting you know timing of action going out. Many of you requested that we be more up front about the action we were taking against players, and you were right in asking for that! Our aggressive action against these players along with being up front and transparent about has led to a fairly substantial change, let me give you some numbers:

Since we started communicating about win-trading and the actions we were going to take, nearly 90% of the previous reports and related win-trading activity have stopped.

In addition, the majority of “trolls,” have stopped their behavior and over 50% of those players have ceased completely.

We hope that many of you are experiencing similar results when you’re playing Ranked. We are going to continue monitoring and taking action as needed. Thanks!

-eric