How about highlighting the current element with an "active" color border, and the next element with a different color for "this one comes next" (e.g. blue and dark gray, or dark and light blue, with the inactive elements being a light gray)? I think this would emphasize the element that comes next, as opposed to making you guess whether focus will move down, to the right, back to the top, etc. The animation is nice, but it doesn't really give you information until after the tab.