Well, most FTL scifis posit only one method of interstellar travel. It's either 1) slipping into a nearby dimension where the distances between points are shorter and then popping back in when you get near where you want to go, 2) warping space so that the distance between point A and point B is shorter, or 3) outright folding space so that two points touch, and then transitioning yourself to the other point before unfolding space. Battletech is, technically speaking, 3. Instant jumps don't fall under 1 or 2.
And I'm okay with that. A scifi universe should make at least a semblance of internal sense. Warp 10 is never going to be possible in the Star Trek universe; it's always 9.938739983 or whatever. Star Wars hyperspace objects can only be affected by normal universe gravity, not turbolasers or Force lightning.
The idea that in Battletech the physics are "maximum jump range = 30 light years" is something that is a constant, and it lets you play with the variables.
What I'D want to see is Sub-compact WarShip cores made common. A mix between DropShip and JumpShip, sized for a group of RPG players to maybe carry some light cargo between worlds, touch down with a few 'Mechs, and generally close up the hole that has always existed in universe. Maybe make them expensive, make them small enough that they simply CAN'T replace the bulk carrying capacity of a proper JumpShip/DropShip pair, but put them IN THERE.
That would change a lot of paradigms in itself. Small bulk, high-value items like datachips and tech gadgets would be more common to sell and spread across the galaxy, raising trade and creating a more modern, unified society. Pirates might adopt simple, tiny-scale thefts rather than massive raids. The value of ASFs and combat spacecraft would raise as well, because it would be the only way to protect a world - without diminishing the value of BattleMechs, because boots on the ground = real power.