I might be able to answer this. Animating SVG is tricky, groups is a particularly issues because each element inside a group has to be animated as opposed to just animating the parent group tag (which causes a lot of issues with rotations in particular, you have to break out the trigonometry in javascript).
I disagree, <g> element can be animated with JavaScript as easily as e.g. <div>. You just change the value of transform attribute. Rotations can be handled easily once you understand how matrixes work.
