Disclaimer: This actually isn't in the works anywhere but is my idea completely.
Mortal Kombat is a great gaming series famous for making parents panic over fatalities, but if you do some research you'll find the game has a rich and deep lore and story ripe for an MMO. Now, when I say MMO I don't mean WoW in the MK universe and with Sub-Zero in place of Varian Wrynn or whatever, but hear me out on this. The game would have no cooldowns but would play like Mortal Kombat in three dimensions, and have an arcade game feel but with deeper battle mechanics while keeping the pace and feel of a fighting game. HP of course replaces a health bar, and armor can be equipped. You of course still have magic (Raiden, Sub-Zero, etc., have magic powers) and melee, and can equip weapon sets that have their own fatalities, which grant extra EXP and guaranteed loot drops upon killing a player. There will also be a broad customization process as far as the player character itself and armor and dyes are concerned too.
What the game will not have:
4.Fall damage, except on certain surfaces like spikes, and being knocked into those would be an environmental fatality.
What will it have?
2.Open world PvP (all servers will be PvP servers)
3.A rich, deep, and complex trading, gathering, and economic system like EvE online, complete even with a system mirroring corporations (known as "clans") that are highly political.
4.Both horizontal progression and vertical progression. Like The Secret World a character can unlock different abilities from different schools, but unlike it will have levels.
5.A mercenary system where you hire out canon MK characters to help you quest and reduce the chance of dying (remember, if you die, you lose everything!)
6.Raids that involve 40 of your closest friends and bosses with high damage and health pools.
7.Level scaling like GW2.
So, how well do you think such a game would do and would you play it? Why or why not? Basically, it would be an EvE online that takes place in the MK universe and has martial arts and fatalitiies with some MMO influences like questing in place of spaceships combat and giving a canon MK character AP to learn their abilities instead of upgrading spaceships.