That's a good question, so I'll answer it honestly from a developer's point of view.

If I had an "MMO"FPS that only had 5k players online at anytime, that would mean I have a few quality fans, just like Dust has. I know it isn't doing good because of the numbers, so I'll have to move on. However, people spent money and time on a game I made plenty of promises on and the hope of evolution. What I would try it to do, is let it die slowly. Not as in MAG, but by the true meaning of evolution. One must die for the other to be renewed in a better way than before.

What I would do, is introduce a sequel. Not Dust 515 (lol), but something like Legion. Same game, better mechanics. I would find out where the players are at and if I just happened to own a forum, I would create a poll asking where the players would like to move on to in a hypothetical situation: current system, or next generation. Depending on the answer, I would try to rethink my options.

A) current generation. Well, I have experience developing for the current system, as well as various assets. I would pull those in and rework them with better graphics and test out the balance. How good and bad weapons/suits are compared to each other. Dust suits felt the same, but with slight modifications. What I would do, is make them more unique. Boost the strengths, and make the weaknesses more noticeable. Work on memory and graphics a bit, if I could. I would talk with my design team and the player base/CPM to find out what was wrong with certain items or maps, and I would try my best to fix it.

B) I would start work on the next Gen as soon as possible. Get familiar with a new engine, figure out what the system could do, etc. It's what I tend to do for fun at the moment. So, yeah, not much I can say here except start anew and try to mimic what works in the first game.

Either way, I know I'm making a new game and I somehow have to get the players to transition from one to the other. So, I would start work on the second game while keeping the first one active and providing a few updates here and there to keep the players satisfied and occupied. When I have a decent playable game (not like the closed beta, but Uprising 1.6) I would give special beta keys to veterans since they know how I work by now and how the game is envisioned to be. They know best what THEIR game is supposed to be like (after the team itself, of course).

Once I have the sequel to where i'm getting close to release thanks to various changes and improvements, I would switch it to open beta and announce it on the Dust 514 Login Screen.

By this time, I would have to figure out how to transfer SP and AUR to their next character, if they redeem it via previous accounts. Isk wouldn't be transferred in my opinion because of broken mechanics such as PC. Kills, deaths, WP, etc would also be reset.

After a certain time has passed, I would mention the date I would shut down Dust on the Login Screen and pull the plug when it's due.

I think this is the best way to move on to a sequel if you're dealing with an MMO with a dedicated playerbase that spend tons of cash on promises I sadly couldn't be able to keep.

TL;DR Move on to the next game while giving players time to transition is best for a MMO with a dedicated player base.

Edit: had to remove a single word. I hate typing books on my phone.