They said the story was the main problem to get new fans. They tried to simplify the story with the Bara Magna reboot and that didn't quite work. Going back to Bionicle would be bad. New fans want to know more about the story but there is just too much to catch up with. I don't see the current building system working for Bionicle.
If Lego were to bring Bionicle back it would only work out in the negative way.
Also later this year or early 2015 a NEW constraction line will be released. A new one, not Bionicle