Is packing sprites not the best way to display them?

[ShatteredReality]

Hi, I posted this sprite sheet and it got rejected

• The sheet contains a lot of blank space or the sprites on it are not organized. Wasted space results in needlessly larger file sizes and disorganized sprites make the sheet much more difficult to use.
  

There is not a lot of blank space so that can't be the case. I used sprite packing software to remove all the blank space between sprites. Should I redo the sprites to make them aligned to a grid (more blank space)?

(The icons are white so it's hard to see on this background).