Just to point out something. . .
Did you notice how many subsequent "rules" you would have to change based on your initial house-rule that a barbarian's rage would end when he went unconscious?
This is the often onforseen conseqence of house-rules in themselves. They often force subsequent house-rules for balance purposes.
Essentially you have ended up treating his rage hit points as temporary ones since they are in effect the first ones that go away if he goes unconscious and then wakes up.
Sometimes, alright usually, it causes more churn in someone's brain when they try to analyze the D&D rules from a real life/world perspective instead of merely treating it as a game with assumed differences that don't require detailed explanation.
I think you are overreacting a bit...
As far as house-ruling is concerned i'm neither pro nor against it. When i do it, i go very thoroughly into the rules so as to make sure i don't create a chained reaction that proves to be disastrous.
I must admit that i reacted somewhat impulsively to the pharse
"Basically it is a conscious action to prematurely end his rage - being unconscious does not allow him to make such a conscious decision." because it didn't make sense as an argument that reaches a decent conclusion.
Moreover i have not encountered this problem with a barbarian before, therefore i apologize for my inexperience with this matter.
However, after reading the barbarian's rage, i thought of it, and i came to the conclusion that i wouldn't like a barbarian (in my game) who wakes up enraged after having fallen unconscious, because that breaks my "in-game" realism and because i believe it is somewhat more fitting to a comedy than my game(s) and the mood i want to establish.
So, by ruling that a barbarian's rage ends once he awakes (so as to protect the character from dying), IMO does not change things a great deal nor does it provoke a chained reaction to my game.
As far as hit points go, curing the barbarian to the point where he regains his consciousness (0 hit points), while taking into account that his rage ends at the same time, means that the healing process has to heal enough of his
actual hit points (without the +2/lvl into account).
Personally i do not see how this treats his "rage" hit points as temporary.
In case it does (perhaps i fail to see something here...) i still do not see how this affects "actual" temporary hit points, or how this change would affects the game beyond that one ruling.