Formidable. But not impregnable.
Observe:
point 1: motivation
Lego is, first and formost, a childs toy. Despite the success of biotubing, most bionicle fans have moved on. As a result Lego would have to draw in a new audience if they hope to even match the sales of bionicle before 2010.
If their primary goal is to attract new fans, it would be in their best interest to create something new using old pieces (isn’t that, after all, what legos are all about?).
In addition, it would give them a chance to rework a fully cohesive story, instead of working around the complicated past. If the story of bionicle is complicated to us (who had the better part of nine years to learn it) how complicated would it be to potential new fans? From a MMO standpoint, it is Legos best interest to build a new story with familiar characters.
Point 2: the evidence
granted the evidence is limitted, being little more than a few leaked pictures. But there is still enough to speculate.
The first is far less than foolproof… but I’ll mention it anyway.
The gold masks.
In the full display pic that was leaked a while back -and gave the first lumps of coal to our beloved hypetrain-, we see that each toa wears an elementally colored version of their mask (ie red for tahu), and includes a gold counterpart.
This implies a “quest for the mask” type story, similar to the first wave of bionicle in '01.
But what’s this? Tahu is wearing a red mask and must find a gold one?
This implies either he has lost his gold armor, or he is on the same level as his toa brothers (or at least, Onua and Kopaka), and not wearing the golden armor.
On that note, by comparing the gold shade of the mask to the “gold” on his armor, we see they are different. Lego has never been consistant year-to-year with the type of gold they use, but usually they have the decency to use the same type within one set.
Tahu’s mask is shiny gold, his arms are YELLOW. not golden armor.
The next point is that tahu is one of the three giant toa… but tahu mata is smaller tha his nuva brothers…
Now, I know what you’re thinking: “but, but… but. but” NO. Stop it. Tahu is huge. Bigger than half his team. And he’s gonna be 'spensive. Get over it.
Plus the other toa’s mask more closely reflect their classic 01 kanohi than their adaptive nuva counterparts (note the three scopes on Kopaka’s mask, as a opposed to the one which signifies the akaku nuva)