sprite sheet with cropped frames is literally only a few kb larger then one that does not.
That depends on how your graphics are created. E.g. if you have a character that is dodging and attacking with a sword it might be a *big* difference if frames are cropped or not.
exture Packer creates bloated pngs
Currently the file size is about 15% bigger then when using opting. This will be fixed with the 3.0.0 release.
lso, never have your character or object change positions in your sprite sheet, per frames. Any change in position should be done by code or game editor function.
You have several cases with animations where this is exactly not what you want to do. You want to keep the anchor point steady while the animation moves around it...