New macbook air (2008) hinge installed; is this new hinge the same or a revision to address the problem? What should I afford to prevent a repeat of this?

I don't think there is something different on the replacement hinge. Best way to take care of the hinge problem is to open it 1 inch less from the limit (travel measured on the top of the screen) and avoid picking up and moving the laptop abruptly with the screen open.

Still if you are going to use it as a backup laptop once in a while hinge wear isn't something to worry about.

My understanding of the hinge issue is that the primary reason for the issue was the barrel assembly enclosure couldn't handle the constant repetition of opening and closing past the acceptable usage angle for the lid. Over time and with enough force applied it would just give out and then the tension coils inside would break out through the relatively thin plastic enclosure.

I do not believe anything was changed with the design or materials when the machines are serviced. The newer models with the "2nd generation" body styling fix this issue more than anything. Not to mention Apple shifted the exhaust vents for the fan to a more suitable place than the bottom of it.