I've always thought Bionicle (G1, that is) had a lot of potential to break away from the toys into a wider franchise, if it were free of Lego's needs (I don't mean that as a bad thing, I just mean that Lego has a specific set of uses for any of their themes and IPs, and ultimately Bionicle will only serve those aims while under Lego's ownership). I think it has the same potential as franchises like Transformers, though obviously that would also possibly mean taking a hit to its integrity...also like Transformers (looking at you, Bayverse).
A while ago, I gave a bit of thought to what might have happened if Bionicle's comic rights had stayed with DC, and honestly came to the conclusion that a comic continuity is probably the best place for Bionicle outside of realm of toys. It's a very visually vibrant saga, and with a few alterations, a G1-retold comic series could actually be something pretty stunning. Just look at what BOOM! Studios is currently doing with Mighty Morphin' Power Rangers; the source material is arguably clunkier than Bionicle, but the comic series has been growing deeper and becoming more thoughtful whilst remaining faithful to the spirit, tone, and characters established in the show. Off the back of this, I feel like in terms of story alone, it wouldn't be too hard to take the same approach to a Bionicle series.
But, in my limited opinion (because I only have a limited understanding of what Lego's motivations might be, and what would be involved in selling the rights, etc) I think it's unlikely that we will see anything of Bionicle for a while. G2 was a failure (in my opinion, its marketing and story were so poorly thought out that it almost, almost deserved to fail) and I think it's unlikely that Lego would take a risk on the franchise for a while. After all, toy stores are going to remember not selling Bionicles, and won't want to stock them. In turn, I think comic publishers would be hesitant to buy something that's sort of tainted like Bionicle is now (financially).
Just my two cents. I could be wrong, but as far as Bionicle's story/engagement potential goes, I think I'm right. I've probably said all this in a really hamfisted way, too, so sorry about that.