Realistic ideas that can be easily applied to the game to make it and keep it viable to mantain and develop.

- Monthly subscription: My suggestion for Spiral Knights is to have a tiered VIP monthly subscription that gives perks and extras to the player; depending on the tier selected, you could get things like Trinkets and Weapons slots, +%Heat Bonus, exclusive medals and badges that show to everyone your support, daily rewards and other minor things like entering exclusive giveaways from Grey Havens for example.
Prices could be tiered like: Tier 1: 5$ , Tier 2: 10$ , Tier 3: 20$ (Most games need some kind of VIP subscription to mantain the development and economic stability of the game. Like 1.battle pass in most freetoplay games, specially battle royales, 2.montly or yearly subscriptions for "premium time" that gives little bonuses over the period of time paid, 3.and premium content such as skins or equivalent equipment like weapons or vehicles depending of the game, with a little twist.)

Thanks to this less agressive funding, there's budget to make new changes, without the need to rerelease accessory boxes.

-A clearer way to understand the rotation of the mechanisms in Arcada and what they offer.
-Community manager that can better communicate the requests and needs of the community players, maybe as a "hobbie" like a Discord Moderator, or a real job.
-A new gamemode similar to Arcada called Crown Hunt or Crown Run, where you have to complete a frenetic room or game to obtain as many crowns as posible in a certain time (for example a 6 minutes game can get you 5kcr), games like monster waves, being accurate with a provided standard gun or other minigames, maybe available only once a day or a week for example, and supporters have more chances.
-A wheel of luck in which you can participate once a day, and the following spins cost for example 20ce, the supporters get extra free spins depending on the tier. The wheel would be different from the Slime Casino Wheel, and this wheel would get you tiny but maybe decent rewards for the cost of a try.
-Reprogram and add crystal deposits, with a basic market to do some speculation.
-Correct errors and bugs that show up over time.
-Improve the capacity and responsiness of the servers, instead of having multiple very little ones, having 2-4 big servers, same for haven when login in English, Spanish, German or French with all those sub servers, instead getting a couple bigger servers, most people know English and/or Spanish fluently, there's no need to separate them by default.
-Making more options and making them clearer to understand, for example, most people dont know they can switch between Europe and United States of America, video options are very limited.
-Giving the community the opportunity to help improve the game, completing missing pages in the Spiral Knights websites, colaborating, not only with suggestions and bug reports, but with actual work that can be done freely, like most community driven games do.
-Being active in social apps like Twitter, Instagram, and posting new changes in the Steam devblogs updates.

-Lockdown:
-New sound when the Lockdown Guardian Shield recovers after being broken.
-Private and public rooms for Lockdown and Blast Network.
-New Lockdown gamemode that uses PvE equipment like shield and shield dash.
-New music tracks for Lockdown
-Optimization and performance improvements
-More stable servers

-Changes for the future:

If the new monetizations work and the game is economically viable to invest in it again, more complex things need to be taken into consideration, things like:

-Moving the game to a more modern engine to make it more visually appealing and with better performance.
-Making a new UI to the game to help make it more intuitive and visually modern.
-Making new promotions and ads to promote the game.
-Redoing the Spiral Knights Website, Forums and Wiki to be more intuitive and suitable for current basic standards.
-Maybe look for new investors who can boost the game and allow you to hire a larger team.
-Get inspiration and resume the development of the story (lore) of the game.
-New content based off of that, new exciting things, not only things like reskins or accessories.

Or maybe you've read all the way here, and you are not sure what to do with the game, if keeping this mummified form of the game, or risking a bit of your teams time to hopefully making the game that came from inspiration from artists truly alive. Maybe there are other less invasive and definitive options, like selling a % of the company shares, selling merchandising from the game to fund it. If you need inspiration, teams like Terraria developers are a great example of what to do with an old game. Or maybe you are just tired of this game, burned from it year after year, maybe it's time to sell it to a company that can manage a game like this.