Eh, I don't think I agree with you M. O. The 4 roles aren't about hit points at all. They are about tactics in general. ALL tactics are about control of a situation. Violence is the imposition of the will of one group upon another by force. It generally presumes that the opposition has its own plan to do the same (maybe just defensively by thwarting your plan, but nonetheless).
Tactics are just methods you use to win a battle. In order to win, you need to reduce the enemy's hitpoints to 0 before they reduce yours to 0. So tactics are, by definition, the methods you use in order to reduce their hitpoints while keeping yours up.
Now, I don't think that you are wrong about the 'three things to do with hit points', this is true, and 4e generally emphasizes hit points as the core mechanic to measure the defeat of enemies by. Its far from being the be-all and end-all of tactics though. Controllers ESPECIALLY deal with the enemies means of fighting very directly. IMHO the 4e controller is the most defined and most central role (though you really MUST have some striking capability to actually win most 'knock down drag out' type fights that tend to predominate in your run-of-the-mill adventures).
I don't think controller is well defined at all. It appears, if you examine all the controllers in the game and their abilities to be the role in which you either do lots of area of effect damage with no special effects at all, or you do single target crowd control with very little damage, or you do single target crowd control with lots of damage, or area of effect crowd control with very little damage, or abilities that allow you escape and protect yourself from damage, or you dispel area of effects that other people have put down. Which seems about as clear as mud.
Aren't "protecting yourself from damage" abilities the domain of the Defender? Isn't damage in general the domain of Strikers? Isn't dispelling a special effect the domain of Leaders?
Here's the real deal, however. "Control" as it is defined in the game is literally just a way to prevent damage to your group. If you cast a spell that prevents the next 35 damage dealt to an ally and an enemy attacks him and does 35 damage you've done precisely the same thing as if you stunned the enemy for a round. If you give the target -20 to hit and they miss, you've done precisely the same thing as stunning them for a round. If you do 200 points of damage in one hit and kill the enemy outright, you've not only accomplished the same thing as stunning them for a round, you've essentially stunned them for the rest of the game.
Which is precisely why all you really need to worry about is damage. It's why our party of strikers not only did just as well as a balanced party, they finished combats in half the time.
My friends and I used to have this argument all the time in 3.5e, we had a couple people who were absolutely convinced that their character was super awesome because of all the defenses they had. Until we replaced them one day with someone who had no defenses and was all offense. We finished battles quicker and the entire party took less damage.
We actually used to get rather angry at people for attempting to "control" in both 3.5e and 4e. Most of the time the controller did almost nothing because they'd put down an AOE that would prevent the enemies from acting and would also prevent all his allies from attacking the enemies. So we'd have to sit around and wait for an extra 3 rounds for the AOE to wear off before we could engage the enemy. When if we could have attacked, we would have just beat them.