Climbing on them would give you an idea how they feel when you're climbing on them.. that's all... and of course, everybody would have their own opinion... which puts you back where you started.
You need a drop sled, too. You can climb on a hank of KM3 Max and say, "this is very static", but the rope has a nylon core, and if you dropped a few hundred pounds onto it, the stretch would be very obvious and it would absorb a lot of energy, which is what you want. You don't need the stretch while climbing, you need it when you're falling.
I think the important data would be how much the rope stretches with two fixed weights... let's just say 250 lbs. and 500 lbs. without dropping the weights, dropping them from two feet, then at four feet, then at six feet. Chart all of that and you'd get a graph of the ropes performance that we can actually use. It tells you a little about how much it stretches just weighting it, and a lot about how much energy it can absorb if something goes terribly wrong.
All of the other rope characteristics are subjective and involve a ton of variables... hard to define in a useful data presentation. But, an ongoing, long-term project could probably make useful data from testing for things like performance with a certain multicender, by developing a test that is independent of the climber. This takes a lot of thinking and planning, but isn't impossible. It would also take a hell of a lot of the arb community willing to participate. That could be a real challenge. I don't think any of the rope OEMs are going to take something like this on.
