#4 Dani Alves
During Rafa Benitez's tenure at Anfield, one of the larger issues were the full-backs. By 2008, Liverpool looked incredibly strong and had a world-class team. However, the problems kept on growing. Alvaro Arbeloa became a first-team regular and was decent, albeit one of the weaker links in the side. It could have looked different for Rafa's Reds had they taken a serious look at Dani Alves back in 2006.
The Brazilian right-back had an agreement to sign from Sevilla and the deal was all but confirmed, but Liverpool apparently pulled the plug on the £9 million move. They would instead go for Peter Crouch and Jermaine Pennant, a move that would be considered a mistake in hindsight. Alves would have been a much better fit for the Reds, with his move to Barcelona coinciding with the peak of Liverpool's powers under Rafa.