Tabula Rasa. It was a first/third person sci fi mmo shooter/rpg with craftable mechs, It lasted for a bit more then a year before it shut down, and no private servers have ever been created.

Gundam : Universal Century Online. Picture Star Wars Galaxies with combined arms mecha warfare. Start on foot, buy a jetpack, mine some ore, built a tank/jet/mech, fight in the war. It lasted about as long as tabula rasa before it shut down. It currently has no private server.

Firefall. First/third person sci fi mmo shooter/rpg with craftable mech suits. bla blah, shut down no private server ever created.

tl/dr: I want a new mech mmo. Or even just to be able to play my old favorite mecha mmos.

Not "revived" since it's still going, but I wish the mega man series would modernize. It's 2024, I get side scroller was megaman's thing but how I would love a modern, ratchet and Clank style platformer/open world where you go to different parts of the city to fight the different robots. But Capcom and most Japanese game companies are insanely opposed to modernizing and of making their games look current. Graphics wise they're always outdated

CyberMage: Darklight Awakening

I'd really like to see another time-based drama similar to The Last Express. It had a lot of time-based events where you could run into particular passengers of the train in the hallways, and gained a strong sense of physical "presence" as people pushed past you in the halls using detailed rotoscope animations.

The Invisible Hours comes close - it's non-interactive, basically letting you play as a ghost cameraman watching the mystery.

I'd like them to give 'Z' (Bitmap Brothers) another go.

Strange Adventures in Infinite Space

Zork

The Darkness.

Jackie Estacado fought through hell to save his girlfriend only for her to get bad touched by an angel and fly away leaving him there to Rot.

We never got to see that story finished.

I really loved playing ps2 military shooters like SOCOM and Conflict Desert Storm. It would be fun to see how those games would be made today.