OK. I'll finally chime in here.
I don't work for the FSE, but I am pretty familiar with this project even though I'm not directly involved. I'm certainly not a spokesperson, and am not directly connected with this project, so my comments are mine alone.
Regarding those who are concerned about falling objects, etc, remember that the old zip line was open for 2-3 years, and I never heard or read about any of these things happening. Not saying they never did, but it didn't appear to be an issue from what I saw and heard. On the old ride, if you had anything that was loose, it had to either go into a locker in the ticketing area, or in a mesh bag that was attached to the back of the harness - flip flops, eyeglasses (sunglasses and prescription), cups, etc had to be stored safely so nothing would be accidentally dropped.
As far as to why it's not open yet, new technology is involved - it's not just a simple line strung between two points. New issues have to be addressed as they arise, and after the project is completed, it still has to go through a lengthy period of safety testing and city approval. So, the timeline is necessarily flexible, which is why an opening date hasn't been announced....nobody knows for sure. Everyone wants to get this up and running as soon as it can be done safely.
The old (short) line was a blast - I can't wait to try the full-length line! The facility is typical Vegas over-the-top....I mean, come on....visitors can shoot themselves out of a giant slot machine and fly past all of the vintage neon and over the crowds? Where else could you do this?