The resistance value of a pickup is an almost useless figure to know. Everything it tells you about a pickup is extremely "rough." It can roughly tell you how much wire has been used to make the pickup...however, that will vary depending on the wire gauge, as skinnier wire has more resistance per unit of length. How much wire has been used in a pickup can roughly tell you how many turns of wire have been placed in the pickup...however, that will vary depending on the wire gauge and the bobbin dimensions. Number of turns can roughly tell you what a pickup's e.q. might sound like...however, that will vary depending on the dimensions of the completed coils. E.g. exactly 5000 turns each on three different types of bobbins will sound three different ways. Then there is the strength of the magnets used...and where they are placed in order to make the coil...and whether they are pole-piece magnets, blade magnets, or under-slung magnets using slugs and/or pole-piece screws to direct the magnetic field.
If all other things were equal, resistance would help you roughly compare the basic tone and rough output of two pickups...however, all other things are rarely equal between two different models of pickups...and output is never as simple as across-the-board power. It's always frequency-specific. So, as you can see, using resistance to determine a pickup's tone will almost always steer you wrong.
IME, the most telling specification about how a pickup will actually sound is inductance. Once you know that, you not only know the rough tone of the pickup, and the rough output, but you can also figure out how it will interact with your particular wiring setup (i.e. pots and caps). I.e., you can design a tone circuit that works best with that pickup, instead of using a bunch of trial and error, like we have to do most of the time when figuring out what pots and caps to use to achieve a certain sound.
The one thing that resistance value is actually good for is basic troubleshooting. If you know what the resistance spec is, you can quickly and easily measure resistance as a way to test for internal problems with a pickup.