It was so awesome killing people with nova gas. Best part of getting tactical mask pro. --- Less is more. Everything you want, isn't everything you need. http://i540.photobucket.com/albums/gg359/ProdigyCashew/pterodactyl.gif
I never used it. Not only was it slow, but you only got 1. If it had thrown faster or if you had spawned with 2, I would have tried it more.
As for why it's gone, it was a part of the story of that particular game so it doesn't make sense to bring it back. Plus they probably know not many people used it anyway.
I played lots of GW/Dom and Nova gas was amazing. It could hurt, kill, thwart, and indicate. All useful tools and loads of fun. It will be missed. --- There is no wrong or right...There is only popular opinion