I am not even remotely interested in 'improving an attacker's well-being.' I would prefer to not permanently damage him too much in the process of bringing the situation under my control, but if there's a choice between my health and his, it was made when he chose to attack me.
To take a similar situation, a patient who is out of their own control in the ER: in that case, I feel responsible for the patient's well-being and the goal is to improve their physical and mental health, ideally to the point that they're not a danger to themselves or others. Still, though, there's a situation where we can put two people on each limb and another one or two for the torso, so there's not a lot of danger for staff involved baring a really unusual situation. Most of these folks don't strike out so much as they just try to escape.
I suppose the overlap would be an attacker who was clearly mentally deranged (ie, hallucinating); I'd feel worse about hurting them than I would feel about hurting random Joe Schmuck trying to take out his frustration for his miserable life in my blood, the same way he would vandalize a public bathroom or uproot a sapling tree in a park. Still, though, his well-being would come second to mine. I don't have some deep-seated sense that putting other lives before one's own life is intrinsically a morally superior position.
So If I read the above correctly then you are interested in improving the attackers well being. So that clears that up.
To say their well being comes second to yours is a separate issue. If you see my view as some morally superior position then I would say you are missing the point.
Firstly the point is to do with martial and I say that is a martial attitude.
Secondly I am saying it is the Aikido view in essence and in alignment with the words of O'Sensei and the Aikido 'path' as a spiritual discipline.
Thirdly and more importantly to me personally throughout my experience in Aikido it is the one most common reason unfortunately that many do not fully grasp or understand what O'Sensei was actually talking about and thus hinder their own Ki development.
Fourthly I will say that unless selfless application is applied with the purpose as described and thus the true Goal in my opinion then those without such will never gain the true fruits of the wonderful art.