Given the limitations, I'd say the best shot, especially for something of military merit, is an improved cloaking device.
I don't know about in the reboot, but in the original Star Wars (that Disney brands as "Legends"), there were two basic cloaking technologies, using hibridium or stygium crystals.
Hibridium cloaking devices could be made with relatively normal materials, but had the huge disadvantage of being "double blind", that you couldn't see out from being cloaked. This was a significant disadvantage that required lots of creativity to make the cloaking devices useful (like in the Thrawn trilogy, when Thrawn launches a number of cloaked asteroids into orbit over Coruscant, creating a de-facto blockade since there was no safe way to leave or approach the planet without risking hitting an asteroid). You CAN fire out of cloak without de-cloaking, it doesn't forcibly lower the cloak, but it does reveal your general location, but not well enough for an enemy to get a weapons lock.
Stygium crystal cloaking devices worked more like the cloaks in Star Trek, where you could see "out", but not see "in". These cloaks were far more elegant, but were also many times more expensive (because stygium crystals were insanely rare and only were known to be found on one planet).
The actual source of the crystals was Aeten II, a planet deep in Wild Space. . .and after the known mines were depleted, the Empire blew the planet up in 3 ABY with the Tarkin superweapon (a prototype for the Death Star II's superlaser) so the Empire could mine the resulting asteroid field to find more crystals. . .which they turned into the TIE Phantom project to make mass-produced cloaking starfighters. . .but the Rebels destroyed them (and the self-destruct took the cloaking devices with them). . .ultimately meaning that after 3 ABY there's no known source for more stygium crystals.
Some way to improve on these limitations would be a major field of research, either a way to synthesize stygium crystals, or a way to work around the limitations of the hibridium cloaking device
For reference, one failed attempt to work around hibridium limitations in the Hand of Thrawn duology was using a supercomputer to mathematically calculate the probable location of enemy vessels based on known locations before the cloak was engaged and known tactics and attack patterns. Cloak during a fight so the enemy can't lock on to you, statistically calculate the probable location of enemy vessels based on last known information, fire in that direction. . .it didn't work.