We're skipping the cake topper. We just love the idea of our entire cake being edible, yum! So I do not think your cake will be lacking without one at all.
BUT, If you LOVE the monogram bling cake topper I say go for it! Weddings cost so much as it is, if there is an item you really, really love and think you'll miss if you do not have it, then definitely go for it! Otherwise on your wedding day you sadly may be focused on that one missing item as opposed to al the good stuff!
Lisa