Considering they say they are still on schedule to deliver Squadron 42 this year, I think we should probably see a new graphics engine soon. They have talked about it being designed for DirectX 12 and Vulcan. It will be backward compatible with DirectX 11 and will run faster than the current engine on that API.
I think you were probably meaning game engine, but they have been working on replacing the rendering engine for quite some time now.
Unfortunately most people's performance problems have to do with the network code and how CryEngine handles objects.
The above is being dealt with in a multi-prong approach. Item System 2.0 allows more customization, better interactions and the ability to glob items together. Like being able to say move ship to here, instead of basically individually moving the thousands of objects that individually are part of, or in the spaceship.
They are also working on only sending information on what you can see.
Right now, you can look at network traffic and know there are 20 people on a ship and everything they have equipped. You don't even have to be able to see the ship.
Multi-theading the servers. Right now they only really support 4 cores. They have 16 core servers that they run 4 instances on right now. Currently they support 24 players per server. This will give them 96, without any other optimization.
One of the major fixes for this will be the dynamic server transitions. CryEngine only updates what is close to a user. This works fairly well when everyone is close together, like in most FPS games, but sucks when people spread out, like in Star Citizen. The plan was always to have transitions between servers, but they are now taking it a step further where a server will service a whole solar system when there are very few people there, but if a whole bunch of people come and are at one space station, a server will be spun up just to handle what is happening at that station.
Just wondering if we'll see the imminent "we're switching to a new graphics engine" announcement at some point.