By less free, I mean that anyone who wants to leave their children the fruits of their labour is now unable to do so. The more restrictions on individuals, the less free a society is. And it is a very big motivator for some people - many people value the standard of living of their children higher than their own.
But I do get your utilitarian argument. After all, every next dollar of our wealth we value less than the previous one. So in this sense, I can see why you would think that redistributing that wealth would make the society better off overall. But I think you misjudge the effects of consumption vs investment and of the incentives on the overall wealth of a society.