Do you remember those crappy ziplines on rats day 1/3? or vantage point on bank heist? and basically every other horrible zipline?
I bet you do, and so do I, that's why I took the effort to let's say 'overhaul' ziplines, their speed to be specific.
Now all ziplines should be balanced or buffed noticably so that all of them are equally useful (not really still, but it's better than before).