I would take dark fantasy or a good scifi(Not so much mecha though) over romance anyday.
I also like real and believable drama, without fantasy or sci-fi elements. That's something you find often in movies but not so much in TV series

Mecha is rarely ever good. The only two mecha series I have no gripes with are Gurren Lagann and Patlabor.
Same deal with slice of life. Good slice of life anime are like Usagi Drop or some older Ghibli movies. One of my favorite manga is slice of life, Yokohama Kaidashi Kikou. Yotsuba& is fun. But slice of life is usually moeblob shit that elicits endless yawns.