Unfortunately, the feedback from when they dropped the F2P plans for STW suggests the game is now "complete." For a long time we expected more story mode for twine, and continued updates when it went F2P. But once they dropped the F2P plans the statements suggested (to me anyway) that the existing content would be cycled, and the game was not being developed further. I'd absolutely love it if that changes, but there's no evidence it will.
I hear you about the trading punks. Sometimes they even try boxing me in thinking I will give in to their demands. Bunch of spoiled brats who need better role models in their lives if you ask me.
If you do want occasional high level rounds with people who won't quit, keep an eye on the free vbuck trackers. Even if you can't get them as a newer purchaser, they will always have long term players plowing through them to completion for the v buck rewards. And 9/10 times when someone quits, those who remain have the skills / builds to complete the round anyway.