There is nothing regal about her, and all her attempts to act that way make her look petulant. The accent doesn't help either, especially when Terminator Genysis proves she talk like a normal human being. Actually, the same thing goes for Lena Heady. For the eyebrows, too. People know what people are supposed to look like, on a visceral level. It's how you know a drawing of a person looks stupid even if you have no understanding of the concepts of perspective and scale and other art-stuff. It's where the uncanny valley comes from. And we are supposed to have eyebrows that match the hair on the scalp. When you don't, people who look at you are too busy wondering what's going on with that and contemplating in what way your main hair is fake. Is it dye? Is it a wig? CGI? If you could afford to do whatever you did to a couple square feet of scalp hair, why not two little lines of eyebrows? I mean, maybe Emilia Clarke doesn't want to go around in her daily life with bleached eyebrows, but I would think having CGI lizards nibble at your tits for record TV audiences to watch would be something that would make you even LESS inclined to show your face outside the house. Clarke would be nothing without GoT. If she really is going to go through all the trouble of becoming an actress isn't eyebrow dye a rather piddling price next to all the rest (such as your face forever juxtaposed with breastfeeding lizards...AND fake-looking eyebrows on said face).

For normal people, with empathy and feelings and stuff, Dany's & Cersei's thick dark eyebrows ruin the immersion like a mispronounced Slavic language idiom ruins Tom's, or white person being better than a black person ruins a SJW freak's.