Most important and fundamental to me is that the VN has routes/dialogue choices in them. Kinectic Novels arent my thing.
After that, its probably the MC's personality (when applicable), if the MC is a irreprehensible douchebag or has quirks which i really dislike, i will probably be turned off.
This is rather very important to the point where i couldnt enjoy Fruit of Grisaia or even non-VN games such as The Witcher series
Then its characters construction (heroines) and overall plot of the VN, as other said, it can go either way (good characters/bad plot,bad characters/good plot), preferbly with both being good
Art comes afterwards, i can basically forgive any kind of artstyle, still VNs like Da Capo did get pushed back in my "to read" list because of... unusual artstyle (Those Eyes!).