The thing is the ride only has a certain (low) capacity. queuing systems won't change how many people get on, just whether they are in a real or virtual queue of some sort. A virtual queue is good if you want them spending time and money in shops and restaurants maybe, but otherwise you're just bumping people from one queue to another.
In a way a simple queue is the fairest means and as long as the queue time is displayed people will choose whether its worth their time or not.
As for adding another Crush, if the issue is in fact that its capacity is rather low, then I'm not sure it would make sense to build another one. The build and operating costs would be the same again and the park might benefit more from a real high capacity attraction.