[Using attitude control]...
We could mount microwave antennas on a nadir-facing surface and provide consistent, predictable, strong, wideband signals to ground stations during a pass.
The problem with LEO satellites is that a nadir facing antenna does give great gain directly overhead ground stations, but only for about the center 2 minutes of only the one direct overhead pass a day. The problem with facing antennas "down" on a LEO satellite is that 90% of the users are not "under it", but to the side of it.
For example, lets say that we put relatively high gain antennas facing down giving about a 45 degree antenna pattern (say around 10 dB). Now looking at the total time that ARISSat is above 45 degrees, turns out to be about 3 minutes a day or less than 10% of all the time it is in view to any one ground station.
But as you say, it is a great advantage if the objective is to provide a 2 minute comm. window to anyone on the planet once a day, then such a design does give as much as 16 dB or so advantage over an omni antenna on a satellite.
Anyway, just a thought. Bob, WB4APR