The current behaviour makes sense. Indeed making pixel-perfect grids (i.e ‘pretty’ layouts) is not the aim of the map view. Rather it is for making sense of one’s notes; if one is pixel-prodding it is not necessarily enhancing understanding. In the current design, the grid is less obvious, there instead being a series of alignment prompts. Or, there is the Arrange menu, where alignment is based on the first selected item.
If more formal drawing tools are needed, i.e for diagrams as opposed to ad hoc map, data can easily be exported and used in OmniGraffle, or Illustrator or any one of a myriad of drawing tools intended for carefully gridded work.
Also, see more on map grids and guides in general.
If you want a keyboard based you could set up stamp(s) that move the selection a small increment in the X plane ($Xpos) or Y plane ($Ypos) and map custom shortcuts to those using the OS or something like Keyboard Maestro.