Do you recommend powders that can be added to ceiling paint to hide some of the imperfections of the ceiling?
Not certain as to what type powders you refer. I have not known of any powder which can be added to paint to help hide imperfections.
There are 3 or 4 texture type products which can be applied to help. I find adding them to paint makes for troublesome applications.
When we encounter this problem and for what ever reason the home owner does not wish them repaired, we will texture over the existing and then paint. I will link this reply so if you like, you can provide more information on the challenge and maybe I can help further.