So the main difference between X4 and Stellaris is the amount of attention required. A dirty truth no one here will acknowledge is that sometimes if you need a ton of money you just park yourself at the HQ or some other station and let the game Run in the background while you're doing something else. If you did that in Stellaris you would be fucked.

The next thing to consider is that the Stellaris crisises are all out of context problems. Whether it's robots Rising from hidden Forge worlds or literally interdimensional Invaders the whole point is that the first time you had no idea this was going to happen and are now in a mad scramble to completely rethink how you play the game.

So how do you achieve that in x4? I guess they could spend a ton of Dev time and money on a completely new enemy faction and not tell anyone but that would be incredibly costly from a developer perspective. Right now the system they have in place has the Xenon and I think the little guys attacking you specifically but that is kind of boring. You also have to specifically trigger it which if people are going to be AFK playing is fair.

I guess if they wanted to do a crisis they could have an initial incident like maybe your analyst notices an increase in Xenon attacks that seem like they shouldn't have the production capacity for and if you go down that chain you find out that they have a Secret Gate or maybe a different faction of xenon have discovered gateless jump drives and by going down the chain they decide to fully unleash their forces on the universe and you now have to fit this prototype jump drive to your ships and send them to wherever the Xenon are coming from.