Considering that most of us here grew up with Bionicle (or were introduced to it recently, welcome to cool world), I view it with tender love as a child bears connection to his favorite stuffed animal.
Be warned, a long road ahead. I still ask you to read, please.
As time passes, however, I cannot say that I do not feel a sense of emptiness from Bionicle as a whole, especially with the rather rushed end of G1 and the cancellation of G2. I would love for G2 to receive actual closure rather than the Toa return back from whence they came. Maybe it is the depressing loneliness in my mind that forces me to think about a LEGO theme rather than my actual life. Or something else, I do not really know.
With this thought, I do still think that having an official G3 would be ill-advised within the next five years, since LEGO just killed its savior brand again. There would little purpose for LEGO to make a G3, because Star Wars Constraction sets are far more appealing and require less maintenance compared to an original universe found within Bionicle. Coupled with the poor sales of G2 compared to newer, fresher themes and constraction sets, G3 has little reason to exist in the future of LEGO.
The only way I can perceive G3 having an official LEGO release is when they would be falling into bankruptcy or some financial matter, as they had during the time period of G1. This would make them pull out Bionicle from its grave to hopefully entice investors and old LEGO enthusiasts into giving them enough money to live again. Looking at it though, LEGO is extremely profitable right now and a decline in sales for them seems nigh impossible in the foreseeable future.
I don't want LEGO to make a G3, the same way you would want to see something you loved be revived as a husk of its former self, Walking Dead-style. We would not know who the target audience would be for G3, either for a nostalgic generation or a younger one. It would face the issue of having to either appeal to the old audience or risk a new formula to get new blood. I have not lived long in this world, but I remember fondly my first memory being the time I received a Nuhvok, all the way back in 2002-2003.
Some time back, I lost the Nuhvok toy I cherished dearly. When these things happen in terms of loss, you ask the world to have what you lost back. And I did. Just recently I went onto Bricklink and bought a new Nuhvok from a trusted seller, almost 14 years after I received the original. Yet, instead of giving me old joy in its return, it salted wounds instead. You see, when your beloved pet dies, getting a new one does not immediately revive the old one, even with exact specifications. I could not understand initially that instead of love and warmth for the one I have now, I have love and warmth for the one I remembered.
And so here we are. G3 does not need to exist officially, since it will call back G1 and G2, due to it being the same franchise. G3 would be born with competition that its older counterparts set for it, which at first seems healthy but comparisons to the old days will be shot at it until its entire existence will be judged solely on it being worthy of the Bionicle name it dares to champion. It would be robbed of the chance it was given by the very same fanbase that wished to campaign a new generation. That is what happened to G2, where expectations were relentless against something that tried to be different rather than improving on G1.
I do not want to generalize this fanbase as a whole, but who was to blame for G2's disappointments? Just the kids who were not interested in an older brand? Bionicle was revived for a reason, and not just for new kids, in truth for us, too. If it was for new kids, why not a new IP in general? Why would you use an older concept besides simple recycling? Look at the licensed themes of LEGO, like Star Wars. Far easier to develop new sets for that, without establishing a new universe. If it was for just us, then LEGO would not have stopped G1 entirely and give us G2. LEGO did not make G2 come easy, evidenced by an attempted replacement using Hero Factory, and when it did come by, marketing was zero. It was a simple message to get across behind a convoluted campaign: Bionicle was over, there was little use in capturing an older audience's attention and appeal to younger ones using this license.
I am not one to throw around conspiracies and stuff like that, and I am not trying to attack anyone. LEGO is a well-meaning company but when something is done, it's done. Only for us, LEGO did something special with Bionicle that allowed us to continue it without their involvement. When things are broken down, it's time to rebuild.
The fanbase of Bionicle and LEGO in general is one that holds a voice over the actual company itself. G2 was revived through our campaigns, made by a community of people who love Bionicle. When G2 was canceled, we were not quiet. G2 was marred by poor sales reflective of our wants and complaints in the direction LEGO was taking its revived theme. People tried to jump off the ship that LEGO had just remade, and as a result the hull busted into a billion pieces from the expectations. The theme we grew up again with was not broken, however, just disassembled. And when things are disassembled, we build again.
G2 did not revive its toyline, but it did renew the community who had hopes for a new future. This is where it took my whole college thesis to this point: community. When one member of the group cannot pull their weight, others pitch in to help them. LEGO fails or succeeds in delivering life to Bionicle again (depending how you see it)- we throw thoughts and theses at them. We plan a universe and how the toys could be constructed- and that's what LEGO is about. We make things. I don't think LEGO needs to make G3, but we could. That's what we are supposed to do by definition of fanbase: expand the official world into a community-driven haven. We could think of concepts about Bionicle and whatnot, and LEGO doesn't have to decide what we make. We do. In the end, G3 is not LEGO's whole responsibility, it's ours, too. G3 can happen without LEGO releasing an official toyline. In this case, an unofficial G3 is something I would look forward to, if it is made by people who care about it rather than them being forced to make it.
tl:dr Sentimentality and poor impassioned rhetoric -> official G3 no, fan G3 and optional LEGO support acceptable