I was just up covering a quilt with feathers and think I may have found the problem of why feathers can take over.
My feathers are blending in. I am using a fine thread and I am and usually use a thread that blends well. I normally pick the thread even on other people's quilts. But I choose a thread that blends so that anything I quilt on their wonderful tops will enhances their quilt but does not take over and is not the first thing you see. You have to get close to most of my quilts to see the quilting, even my own where I can go outrageous. It is like a secondary design not the main thing.
I have had people specify thread in bright contrasting colors and I warn them it is going to show. If you pay the extra money for feathers you want them to enhance but not take over usually.
The opposite problem I have encountered was a beautiful top in a quilt show, gorgeous colors, beautiful piecing, with the large background pieces meandered. I was so sadden that this gorgeous wonderfully done quilt did not have feathers that gave beauty and specialness to that area. But of course I wanted them to lurk in the background and only be seen when you were close to the quilt.
I hope you will look at the quilts where you do not like feathers and find out why they are taking over the patchwork. Then work with your longarmer to avoid that. It is as simple as telling her to make sure the quilting does not overpower the patchwork you have done.