This will be a very cool feature to see sometime in the future. The sim already has fog, so I don’t think this will be too hard to implement (maybe the animation part). In case you don’t know what I’m talking about, here it is.
~ Erwinvandijck on YT
And here it is, in action.
~ Schipholhotspot on YT
All in all, this will make takeoffs more realistic, and should only happen when the dew point level of the engines is the same as outside of the engines.