In trying to understand both Makuta's plan and the outcome of 2008, I have been racking my brain and I believe the most important question is "How much exactly does Teridax know, and how much of this has he actually implemented into his plan?"
I have no idea what the inner, knitty-gritty details of Makuta's plan is, but, at least currently, my guess is that he knows and is planning this much:
Makuta, still in his energy form, escapes to this undisclosed location to prepare his final steps. He is going to try to possess Mata Nui, but he needs time to finish his preparations, and only the six Toa Nuva can awaken Mata Nui. So six of the best Makuta have been assigned to deal with the Toa Nuva- even though these Makuta have been instructed to keep them alive- So really, they are only stalling. None of the Makuta know about the power storms, and, since their minds were wiped, neither do any of the Toa Nuva. Out of greed, Icarax will also join the other Makuta in their raid of Karda Nui. After just the right amount of time, and when Teridax has completed his task, the Toa Nuva will manage to awaken the Great Spirit, whom Makuta has now managed to possess. Lightning Storms will ravage Karda Nui, killing every living thing in it, including the Toa Nuva and all of the Makuta. Makuta will awaken as the great spirit, effectively leaving him in complete control, and, having effectively killed off the 13 beings most likely to usurp or cross him and pose any real threat, with virtually no one left to oppose him. Makuta Teridax will have won and thousands of years of preparation will have paid off.
That's the tail end of the plan, as far as I think.
Now, again, I ask myself: "What exactly does Teridax know?"
We can safely assume that Teridax believes that Miserix is dead. Else he would have killed Krika, don't you think?
I do not believe Teridax counted on Takanuva showing up or the Ignika turning into a Toa, and even if he did, he didn't think it would be that bug of a deal.
I was thinking, and I read somewhere that Mata Nui cannot be awakened until a certain period of time, and that if perhaps he was awoken a bit late, it might pose a bit of a problem for Makuta Teridax.
This I was thinking about, and I think I've got it.
Makuta is counting on the fact that the Toa want Mata Nui awoken sooner rather than later- after all, 1,000 should seem like enough time! But he did not count on the fact that A) Krika had feelings of sorrow and pity that other Makuta did not have, and B) did not think that Takanuva would show up C) Even so, Takanuva would not know about the electric storms (how could he?), D) That Takanuva was not going to immediately feel such a strong bond with the Matoran. To quote Takanuva's blog, "Right then and there, I swore that no matter what – even if it meant Mata Nui stayed asleep, even at the cost of my own life – I would see to it that the shadow Matoran were cured." That right there is what did it for me. That sounds like a deliberate hint.
So here's my theory- The Toa will want to awaken Mata Nui sooner rather than later, but Takanuva will stop them, telling them of the storms (we know he does this already cuz of the blogs) and that he will not let all the Shadow Matoran die. He will do everything he can to stop them, and eventually the Toa will reluctantly agree, and heal all of the Matoran and effectively evacuate them from Karda Nui. Makuta Teridax had not been counting on this, and was sure the Toa would have acted earlier, and now vital timing elements of his plan are effectively destroyed, taking a large toll on his plan. The Toa Nuva manage to come up with a way to awaken the Great Spirit while staying protected from Karda Nui's electric storms. Mata Nui will in the end awake normally, and justice will be quick and harsh on all of the Makuta.
However, I can't ignore the role of the Hagah, who are trying to look for him, or the dark hunters and OOMN, who seem to be at war with the Brotherhood.
I believe that Miserix may be a red herring. Greg said he isn't really looking for Teridax, but just trying to scare people.