Why Do Not Alot Of People Play Lissandra Anymore?

I've been playing Lol for almost a year and I have played alot of games. I have noticed one thing I've seen many different champions in my games and I know that champions I haven't seen are being played via youtube and NA LCS but I have never ever seen or heard of Lissandra being played recently. I just want to know why because she seems like a really good champion and her ult seems like total bullshit. Her abilities are great so why isn't she played more often?