You know, when I listened to the last Podcast I was against it, and I still mostly am, but as I was voting I could see the reasoning.
A big part of Bionicle for me is the characters and the aesthetic. I was always into the story, and I know it's almost the sole factor why Bionicle has endured for so long, but for me even something as shallow as "I think these characters look cool and have interesting personalities" was a big pull factor.
I prefer it as constraction line for that reason, but I can see that for the people who place the story and world above everything else that a System line would better allow for a physical representation of places, landmarks, and landscape. I wonder now, what if the second question was flip-flopped?
What if Bionicle was a mostly constraction theme with some System sets for the landscape and landmarks?
@Jon @Mesonak Also, I think there should be a poll, or at least a discussion on what people think the essence of Bionicle lies in. As I mentioned before, I think the preference for which side of LEGO it should reside on is determined by what one interprets Bionicle's key essence is. Tagged because I want them to see this, at the least Meso since he has some very interesting discussions on the essence of Bionicle.
For me, it's the characters, their design, and the aesthetic, hence constraction preference.