Combat rank as a way of adjusting AI difficulty would be a lousy choice - i'm sure Frontier know this, and I doubt they'd use it. This is for 2 main reaons;
1/ It means sod-all. Seriously. Pre 2.1 it was easy (if you had the time) to become rich by grinding out Smuggling in Robigo. Having done that you spent the money on a ship with good shields and turrets, popped into a RES, popped your hardpoints open and watched endless NPCs suicide themselves. Each one of those NPCs was a "notch" and you eventually made rank. Whilst watching netflix in the other window. Also it doesn't reflect how hard the kill was. Blow away some unshielded hauler with an Anaconda, or manage it the other way round. It's still a "kill" and effects your score equally. I think we all know which commander is the better, though.
2/ The game is MMO, and needs to share it's decisions across multiple commanders. So "Mostly Harmless" CMDR Trades2Live is in a Nav Beacon, trying to scan it. Low-ranked eagles and sidewinders scan him in his T7, they will attack in a few seconds but as he can't be mass-locked by them he'll still have time to high-wake before his shields pop. Suddenly "Deadly" CMDR DEATHoNa5Tick arrives in his FDL, and dangerous-ranked vultures and Anaconda spawn to fight him. Or do they? If you spawn for the MH guy, then the Deadly guy is going to massacre them and it's no challenge. If you spawn for the Deadly guy, then the MH chap is dead in seconds thanks for waves of Dangerous/Deadly/Master combat ships spawning to fight with Deadly.
But. Why bother with all that at all?
In the game the player can select the range of risks they want to partake of. Don't carry expensive stuff into high-risk areas, don't annoy influential and dangerous factions excessively. Don't fly ships that attract attention to you. It's all very close to real-world crime provention advice, actually. Don't take jobs for the local Mob and expect law enforcement to turn a blind eye. Just like in real life. If you want a stress-free experience, pay off your bounties, repair your reputation with the factions and settle into a high-sec system to do mining or SRV exploration. If you make the NPCs also follow similar rules (top tier bounty hunters only go after top-tier criminals....bad pirates only bother with worthwhile victims - etc you can make the player self-adjust quite nicely.
That's why I don't think Combat is should be (or IS) used to determine spawning. I think that determines that is the player's wider actions and decisions within the game.
1/ It means sod-all. Seriously. Pre 2.1 it was easy (if you had the time) to become rich by grinding out Smuggling in Robigo. Having done that you spent the money on a ship with good shields and turrets, popped into a RES, popped your hardpoints open and watched endless NPCs suicide themselves. Each one of those NPCs was a "notch" and you eventually made rank. Whilst watching netflix in the other window. Also it doesn't reflect how hard the kill was. Blow away some unshielded hauler with an Anaconda, or manage it the other way round. It's still a "kill" and effects your score equally. I think we all know which commander is the better, though.
2/ The game is MMO, and needs to share it's decisions across multiple commanders. So "Mostly Harmless" CMDR Trades2Live is in a Nav Beacon, trying to scan it. Low-ranked eagles and sidewinders scan him in his T7, they will attack in a few seconds but as he can't be mass-locked by them he'll still have time to high-wake before his shields pop. Suddenly "Deadly" CMDR DEATHoNa5Tick arrives in his FDL, and dangerous-ranked vultures and Anaconda spawn to fight him. Or do they? If you spawn for the MH guy, then the Deadly guy is going to massacre them and it's no challenge. If you spawn for the Deadly guy, then the MH chap is dead in seconds thanks for waves of Dangerous/Deadly/Master combat ships spawning to fight with Deadly.
But. Why bother with all that at all?
In the game the player can select the range of risks they want to partake of. Don't carry expensive stuff into high-risk areas, don't annoy influential and dangerous factions excessively. Don't fly ships that attract attention to you. It's all very close to real-world crime provention advice, actually. Don't take jobs for the local Mob and expect law enforcement to turn a blind eye. Just like in real life. If you want a stress-free experience, pay off your bounties, repair your reputation with the factions and settle into a high-sec system to do mining or SRV exploration. If you make the NPCs also follow similar rules (top tier bounty hunters only go after top-tier criminals....bad pirates only bother with worthwhile victims - etc you can make the player self-adjust quite nicely.
That's why I don't think Combat is should be (or IS) used to determine spawning. I think that determines that is the player's wider actions and decisions within the game.