It’s amusing to think that JJ (perhaps inadvertently) forced them to go in a creative direction by pushing Luke out of TFA.

JJ: 'Let’s make Luke the mystery box at the end of the film, so he doesn’t suck the attention away from our new characters.'
Rian: ‘Hmm, we need to figure out what awesome secrets this island must hold to draw Luke away from his friends.’

JJ: 'Let’s film on an island with some old stone buildings, that will be cool.'
Rian: ‘Hmm, we need to create some interesting alien caretakers for these buildings, since there’s no way they would have survived this long left to the elements.’