Covering ground doesn't always equate to being tactically aware though. When we played Gerrard and Alonso in the middle at Arsenal (and in Istanbul), both were fucking dire as a partnership, they left holes everywhere and we got destroyed as a result. Alonso did put his foot in and he also worked hard, but he could also go missing too when the chips were down, particularly early on in his Liverpool career. He was brilliant obviously, but he had flaws he had to work on, so did Gerrard.
Rafa's decision on Gerrard was two-fold. He saw that he couldn't always be relied on in particular setups as a more orthodox central midfielder, and he knew if he lifted the shackles off him, he would do more damage to the opposition. His record on the right and then behind Torres saw him reach his full potential, which was no surprise to anyone really.