The akratic is the person who wants to abstain from something but gives in to temptation. So for example the akratic wants to be healthy and believes eating icecream will cause him to be unhealthy, but eats icecream anyway.
A plausible story about the akratic explains the conflict between the desire for health and the indulgence in icecream in biology. Our brains evolved in a calorie-poor, fat-poor environment. Consequently eating high calorie foods feels really good. Our capacity for long term planning and rational thought evolved later and is instantiated in a different part of the brain. The akratic is experiencing a war within because he is not just a mind but an embodied system that evolved.
This raises the question: would we like to be free of akrasia if we could? It helps to feel our way through the issue by imagining what someone free of akrasia would look like. Such a person would feel pain upon failing to get what they desire that was every bit as intense as bodily pain. For such a person acting in an unhealthy fashion (or otherwise failing to live up to their highest aspirations) would cause a pain as intense as stepping on a tack. And, not to be overly obsessed with the punitive, the pleasure of successfully completing a project or following a diet would be as intense as bodily pleasures are for us.
How would that work? We would only need to make two simple changes. We already respond to loss of money as a sort of pain and gain in money as a kind of pleasure. We would simply need to be neurologically or psychologically altered so that a significant financial loss caused actual physical pain and nothing else did, and a significant financial gain would cause actual physical pleasure, and nothing else would. We would also need a rational free market, so that for example if we followed a decent health regimen our health insurance would be cheaper, and if we indulged it would be more expensive.
Such beings would never cheat on their diets because ice-cream would not give them pleasure, but a drop in health insurance premiums would.
Are such beings imaginable? Realizable? Coherent? Desirable?
My guess is that they are not actually coherent and certainly not desirable. If that is correct than akrasia is not actually a bad thing — it is the inconvenient aspect of a deeper aspect of being embodied humans.