Unlike GoT the characters aren't developed enough for the audience to be invested in them, there are few memorable moments or dialogue/lines (name me 1 good quote).

The pacing is terrible, there are episodes where hardly anything happens, too much is compressed into too short a time frame to give it much meaning but at the same time the story seems drawn out, it's not very good story telling. You can tell it was developed by committee.

The casting is terrible - the entire conflict and story arc revolves around succession to the Iron Throne and talk of "pure blood" - if this is the primary concern of every charter and presumably the people they rule, why do people look so different with the exception of white/blonde hair? It doesn't fit in the world we are being brought into.