When you loosen the collar and allow the sway bar and bushing to slide down the shaft, will the bar force the whole link to rotate? In other words, if you moved the shaft out of the way and rotated the sway bar down towards the lower mount, is the lower mount in the arc swept by the hole in the bar? If not, then you could end up with some unintended forces when the bar and collar slide all the way down the shaft.
You may not have as much of a problem with it bootless if you don't live in the rust belt, but I would think that you would want to be able to lube that thing.