Imagine trying to eat with a sheet over your mouth. That is what it's like for the soil under weed block! How do worms and other critters get in and out? The only time I recommend the use of landscape fabric is when rock or gravel is being used, and I rarely recommend THAT! You will have excellent weed control by clearing the ground of perennial weed roots and annual weeds (by spraying or digging) and then mulching with organic matter. The mulch prevents seeds from germinating, and seeds that blow in are easily controlled with pre-emergents. The organic matter will feed the soil (and its inhabitants) as it decomposes, and everything will be happy!
By the way, your observations are interesting!