I wouldn't say he's rubbish because of how the computer uses him, any player is rubbish if not used well.
He has the sats you want of a AM or RM although lacking pace and dribbing so not a winger. Hence you don't want him up with the forwards on the wing, which is probably what the CPU does with him. And centrally I don't think he suits the MCa role, and definately not MCd. Pretty much what you want in a playmaker, just doesn't have the defensive skills to play MCd/DMC.
Personally I haven't used him, but would think he suits a 4-4-2 Tight-Diamond (2xMCs rather than LM+RM) or 4-1-3-2 with a good wingback to give width. Two forwards and a AMC ahead of him to play through balls for. MC left, DMC and right wing back around him for support, plus space to his right to move into crossing positions. With the DMC and two DC you have good defense so can afford to attack with wingbacks more but can keep beckham deep enough that he isn't wasting the MCa role like in a standard 4-4-2.
