My understanding is 25K pots are typically used with active/low impedance pups. If so, would using the 25K volume without the buffer or blaster before the volume compromise tone? Too trebly? I don't have either onboard yet (in the queue to do)...but I just realized I do have them in my effects loop (pedal) so the volume is seeing the same thing (albeit with addt'l 15 ft of cable). I haven't noticed a noticeable difference when FX loop is off (no buff/blast), but I haven't been looking for a change either.
The higher the resistive value the more high frequencies will get through, the lower resistive values will attenuate the high frequencies. A general rule is 250k for single coils and 500k for humbuckers. The 25k pot is used to keep the resistance low for the low impedance output of the buffer to eliminate the filter created by the interaction with the cables capacitance. Using a 25k volume pot on your pickups without a buffer will alter your pickups high frequencies in an adverse way.