There already is a Show Grid on the layout view thing, right by the grid size and snap to grid options.
The image editor could use some work, however I do suggest that if you're going to being doing a lot of pixel art, to do it outside of C2 as you get access to many many many features that are not priority at all.
Many modern image editors/pixel art programs have layers and etc. C2's image editor is like MSPaint atm.