I had been considering this, for my Traveller setting, mainly because of where it is set.
Essentially, I've created a new Sector which was colonised centuries ago following a misjump, and a huge 10 parsec gap seperate it from the closest star system. So they had worked on finding way of getting a 'better' FTL system tthat allow them to go further then what the curent FTL system can do, in order to reestablish contact.
So in essence I have 2 FTL system, the 'core' one for everyone and this alternate one for an 'alien' human culture who shows back up on the radar avec countless decades. Creating by itself a lot of interesting game and plot situation.