Per the dev team's message on the game's official forum:

Dear community,

We’re sorry to inform you that we will be sunsetting Ghost in the Shell: Stand Alone Complex First Assault Online in North and South America, Europe, and the Oceania region, with final closure scheduled for December 6.

This was a very tough decision to make. The game has been in development for a long time, supported by developer, publisher, and community effort. Ultimately, we decided that continued development wasn’t going to help the game become what we all hoped it could become.

We will be supporting the game for the next several months during the sunset period, allowing both the development and publishing teams and the community to say goodbyes and enjoy the game.

In the near term, we’ll be removing the in-game store and will stop selling Steam DLC immediately.

After several months, the game service will be closed for good on December 6, 2017 at 10am PST.

It’s been a humbling experience to serve such a dedicated and engaged player community. We sincerely thank you for all the feedback and support you’ve given us throughout the years.

It sucks because there's definitely a good game to be made with the Ghost in the Shell franchise, and this one was entertaining for a short period, but ultimately First Assault was a standard multiplayer shooter with Stand Alone Complex skins and returning voice actors. Maybe they were hoping the live-action movie would boost their numbers, or that the "2.0" rollout and class-based loadouts would satisfy newcomers, but whatever they had planned, it's dead now.

In the meantime, just watch Stand Alone Complex (again) and pray that whatever the next adaptation of GitS, it comes off better than the last few multimedia attempts (looking at you: Arise miniseries, live-action movie, this game).

I'd really like to see a Ghost in the Shell game take place within a Deus Ex-like framework. I don't recall ever posting this, but I've had that thought since playing Human Revolution on PC the first time several years ago.

Huh, another botched multiplayer FPS published by Nexon. That company seems like poison to me.

I've had the exact same idea for the longest time, GitS fits perfectly for that kind of game!

It really does seem like the most ideal genre of game for the series, that or possibly some small XCOM like tactics game maybe.