I agree.
However instead of making a node's border snap to a gridline, I would make the size snap to the next unit of grid spacing. So a node's size could easily be maintained in units of grid spacing regardless of center position. Then you can move the center magnetically to the desired position.
Because aside from changing node text, the reason for resizing a node is mostly to make room for more othogonal connectors on one of its sides, which are spaced by grid increments already.