No twist? Usually the sway bar must pivot in its bushing as either side of the van's suspension gets compressed. That changes the angle of the bar's arms relative to the horizontal; not much, but some depending on your suspension travel. I suppose it could all be done with just the torsion of the bar, but I would think on our vehicles there's gotta be some pivot at the end of the top link. There is on mine; that's why I have to make the van completely level to hook up again. And lots of end links use heim joints for that reason, I suspect, so that the angle can change. Mine uses bushings, and pivots a bit at both ends.
Here's a heim setup; I'd use something similar (it's also like what ujoint uses) if I had to replace mine, but again I'm still thinking of a quick disconnect. But if I have to go non-quick I figure the heims might make it easier to unbolt and bolt back on. Dunno.
If the right angle formed by the pin from the bar and the end link were to change in or out (with say some side flex) then the two pins would bind, and be subject to being twisted right off.
But hey, I'm just speculating based on how mine work. I got the van up on a rock to see how it flexed and it was more than I expected. Thanks tons for your suggestions.