Guild Wars 2's World vs World mode, but with an established IP and without the bolted-on single player content. And increase the team sizes while you're at it. Sell cosmetic DLC to pay the bills if you must.

WvW was a blast until they shelved it for a year to focus on poorly-written single player DLC, and lost half of the community in the process. I tried going back a few years ago but it's a grindfest now.