We'll have to wait and see what the KWS changes end up being in game, but it sounds like FDev are really trying to make the benefits the same, but work with the new system. However, I feel like the KWS changes would be more palatable for more players, if some of the other KWS module stats are adjusted as well. Namely, scan range, scan time, and power draw. I propose that the KWS is no longer a manual secondary scan, but instead, works passively through your ship's own sensor scan. To maintain a trade-off, the KWS could reduce scan range, and increase scan time, and could also add to thermal load. As you progress from E rating to A rating, the penalties get less, but perhaps not zero at A rated. And you can engineer sensors and KWS to help offset the penalties.
This would make kill-warrant scanning a much less tedious affair, and still make it take longer than a normal scan to gather this extra information. If you are done scanning for warrants, simply disable the KWS in your modules list, and your ship scan reverts back to full range and normal scan time. Want to scan ships for bounties again? Then turn on the KWS. But what if you scan a ship, but forgot to turn on the KWS, and the passive scan has already completed? I assume that the game tracks a variable state on each ship, whether it has been scanned or not; ships are scanned the first time targeted, but after it's completed, no more passive scan. It would only need to track if it was KW scanned as well, and if not, it runs the scan again, if you turn on the KWS and target a ship.
Power draw also needs tweaked, it's a bit excessive at A-rated. A linear increase in power draw would make more sense than exponential growth, especially since the only current benefit is a slight increase in range, but no change to scan time. I'd suggest that if it's going to remain a manual scan, drop the power draw a bit, to 0.2MW increase per rating. If it becomes passive as I suggested, that may justify it being so high. Another idea, if it is to remain a manual scan, is to drop the power draw a bit, and instead draw from the SYS capacitor while scanning. Then it becomes a trade-off of scanning your target, but risking making yourself a bit vulnerable if you bite off more than you can chew, as your SYS may be drained, delaying shields from recharging if you get hit hard by that ship. Or that might become annoying, I don't know.
The KWS could also generate heat while scanning. It would be generating more heat than your ship's sensors, because it's not simply scanning a target close to you, it's also straining to communicate with the Nav Beacon much farther away (I assume the Nav Beacon, unless there are other beacons or satellites strewn about every square AU of the bubble that connect to law enforcement databases, which seems ridiculous).
Just my thoughts, I'm looking forward to the 3.0 update, and I'm sure if the KWS is universally hated after that, it can be tweaked and fixed. Maybe we can at least try it and see for ourselves how it works, before assuming the worst and running away with that.