I went the opposite way, to a 200mm crank, which in relation to my height is equivalent to an average height male on a 165mm crank. My RPM dropped only for a week or so, then climbed back up to the 80-120 range it was before.

Bottom line is, you have to have the range of gears to support the majority of your riding at the RPM you prefer, preferably staying toward the middle of your rear cluster most of the time. Just observe how you use your gears and adjust the range accordingly.