I admit that I haven't played her but she seemed pretty decent when I faced her as Ziggs
So she was able to hold her own against a turtle champion that is low threat.... great
here is why is she is bad
http://champion.gg/champion/Taliyah
Non damage ult, Highly conditional Q that is easily dodged, E W combo that counts on the high latency of players in order to work. A skill cap that ever zed player claims that zed has.
I am not even a Taliyah player but i have seen her played enough to understand her problems. I am not sure why you use your one of as justification of her strength. You are not even a mid main (as far as ranked is concerned). Why would you think that someone holding out against you is positive in a meaningful way? When i end up mid (as a jungle top main)and someone does not beat me it shows 1 of 2 things. The champion is either weak or the player is garbage. I did not beat them, they failed to take advantage of my weakness.
This post is a prefect example why you have not hit gold again this season.