both things are important
this kind of discussion are important too because game devs can think of ways to create games with different approaches.
i really like story in games and nice gamaplay too, but if i dont like the aesthetic or the universe inside the game the gameplay or the story/plot will not make me play it more than once. ex: gears of war, CoD, bioshock, last of us.
this not make this games good or bad, they just dont work for me.
i think if you try to make your work appeal to everyone you will be doomed to make tasteless things; ppl who dont like story will not be fond to play a game like 999(9 hours, 9 persons,9 doors) or remember 11; and ppl who dont like specific kinds of gameplay will not be fond to play CoD or Halo.
a curious thing: i dont like Halo, Halo 2 and Halo 3, but i'v loved Halo Reach JUST because of the customization and the coop
sometimes i'm hooked by curiosity of some game premise, like yume nikki or Ao Oni and i'm surprised by how the game works, wich is very cool but if you think about why i like it, i think is because i did't have a high spectation about it and i think this is a great factor to make someone play your work: how you present your game?
your game looks like something that was made before?(comparable with some other games?)
what you want to tell to the players and how you want then to feel about it before they even try it?
my conclusion: gameplay and story have different meanings by different persons, both matter even distant of eachother. i think your effort will be more well spent toward how you want ppl to feel while playing your game, happy? sad? angry? want to make a question to the player? want to make it have a good time while playing? want so surprise then? or just want then to stressout?
no matter what you choose to make, will always be ppl who will love your work and ppl who will hate it.