Storytelling in VN is importent for me. Also good Sex and Animations. I think it goes Hand in Hand. If the story is good, the Sex-Scenes work better. And for some Creators, Storytelling seems to be harder than the Sex-Scenes. LASTO, who is working on Siblings Delights. I have downloaded maybe 5 or 6 Versions, updates, restarts and I hope he gets everything together soon.
A good game absolutely must have balance between the two.
A game without a story can't be called VN, and a game without mindless sex is one that takes itself too seriously to be fun.