I hardly think the Soulknife sucks, what with Knife to the Soul, but whatever.

+5 each would be good, I guess. If you really want it to be +10 each, I think that'd work if you lower a save and drop 'em to 3/4 BAB. Mechanical class balancing isn't my specialty, but I do know that a +10 sword and +10 shield is overpowered. It's not exactly difficult to make the sword two-handed, too, what with Animated being only a +2 shield bonus.