P.S. many people would question whether there is such a thing as hard and soft aikido; including myself (I think). Basically, if they are soft in their attack, you attack hard; if they are hard, you are soft. I think many problems in aikido really come down to the realism or sincerity of the attack. (I hate these attacks where someone goes to strike you but ends up running straight past you, what are they really aiming to do? - bokken practise seems to be a good way to remedy this, 'cos if the attack isn't sincere you can easily see it).
Also, I have heard about this concept of the circularity of the aiki movement just being necessary to set up the opponent for the most prone position so your power can then be fully utilised (although obvioulsy you don't want to kill uke).