The way I see it is that both Strain and Wound are abstractions to determine the general well-being of the character. Strain represents mental strain, while Wound represents physical stress. Actual physical damage, to me, is represented by Critical Wounds. When you take wounds, I see it more like pushing your body to do what you want it to do, straining your muscles, or taking bruises and cuts and scrapes. When you reach your Wound threshold, it means that your body can't take any more abuse without something snapping (Critical Wounds). So a stimpack is more akin to an athlete getting a cortisone injection in his knee, except instead of just masking the pain, it revitalizes the character's health and boosts his natural healing ability. A stimpack, of course, won't do much of anything for actual damage, like a broken leg or a blaster hit to the gut. For that, you need more specialized medical attention, which the rules do a good job of spelling out.
So, honestly, I have no problem with Wound and Strain (and Critical Wounds) staying the way they are.
Exactly this is what you have in games like TOR (and many others, I just refer to TOR because I am playing it a lot recently), and that is what I want to create with the "Endurance". Notice though that the designers of the game had a different idea for what wounds mean:
Wound Threshold: A character's wound threshold is, basically, how many wounds -physical damage- a character can withstand before he is knocked out.
But if you read the sidebar on the same page (pg 215), it clarifies what it means to take "wounds":
- At this point, he's suffered a few cuts, bruises, and scrapes. However, he has not taken any permanent or incapacitating damage. He's a bit battered, but he's still hale and hearty overall.
- Critical Injuries are actual injuries that have some sort of detrimental effect. A character may be critically injured and wounded.