I think the argument was more that Sephiroth remembers himself through the memories of others, Like how Cloud is feeding of Tifa's memories of him. But at the end he regains his own memories of "who he truly is".
It seems like we have instance both of the Dev's saying that Sephiroth is totally in control and that his actions are controlled by jenovas will.
So I understand saying it's uncertain, but I don't think seeing Jenova call to people is at all proof of either or that the video makes any strong...
Concluding that it doesn't like the things we humans enjoy thus it's not sentient is silly. Perhaps seeing new planets and sucking out lifetimes of memories is more fulfilling than anything we could do in our lives and is so much fun that Jenova has no problem doing it until the end of time.
I...