I'm sure more small holes would be better. I thought about that quite a bit too. I have a fish tank with a bubbler and under gravel lift so have some idea about the water movement.
My thinking is that even though I could get smaller holes I wanted something that I could clean well at least once a year. Smaller holes would be almost impossible to clean. As for air bubbles, a bit of pressure seems to give pretty small bubbles. They are discharged so quick that they don't have time to "inflate" to any real size. When I back the pressure off and slow it down the bubbles are still fairly small but a bit larger than when it has more pressure.
