In a 442 formation, CM for me. Love to see Gerrard steaming forward from the center of midfield with two strikers and maybe some wide men ahead of him providing options for Gerrard and a dilemma for the oppo, plus of course at CM his outstanding defensive and long range passing abilities are also brought into play. Rafa's selections however apparently suggest that he doesn't think we possess a striker of sufficient quality to play alongside Torres in a 442 and therefore 4231 will be our preferred formation until the partner for Torres situation is resolved.
I agree that Gerrards looked good playing "behind" Torres in a 4231 formation but from that position if Gerrards' forced backwards to assume some defensive responsibility Torres (or any lone striker) is left isolated and becomes little more than a spectator, again highlighting the need for us to bring in more quality in the wider areas to provide more sources of supply.