A lot of people have formed opinions of these sets based on height. Some of these are reasonable. Some of these are not. I'd like to offer some of the info I managed to put together from the newest images.
"Bitil/Gorast is too short"
Hardly. The base of Gorast's head when the legs are stretched out (You have to assume a knee joint on Matoran legs, but this is typical of all accurate height measurements) is exactly the height of the base of an Inika's neck. Her legs, when outstretched, are likewise the same height as Inika legs. Her height with neck stretched vertically is therefore 28 modules, not counting the extra height added by her mask. With neck horizontal her height drops considerably to 24 modules, but I have yet to see an official image of Gorast in this hunchbacked pose.
Meanwhile, with his neck stretched vertically as seen in the S@H image, Bitil is in fact the tallest of any of the Mistika, at a whopping 29 modules. A horizontal neck places him at a shorter 25 modules. For reference, we have never had a Toa set of this height besides Takanuva. The maximum normal Toa height encountered so far is 27 modules on Onua Mistika, Jaller Mahri, and Nuparu Mahri. 26.5 modules is the height of a Toa Inika, and what I typically regard as the "normal" Toa height for Toa of 2006-2008. 25 modules is just the edge of what I regard as "normal" height and posture, and is the height of Hahli Mahri or Tahu Mistika.
"Krika is awesome because he's so tall"
Krika... poor, poor Krika. Assuming his rear leg blades are 10 modules tall (a reasonable assumption), his legs are like Gorast's the same length as Inika legs when outstretched (remember that this is impossible in the set, but necessary in determining his true height). 16 modules, the longest we've ever seen legs on a canister set besides Lewa Phantoka with his taller-than-average feet. Fair enough. Interestingly, Antroz's legs and torso are the same height as Krika's. We find that from base of "feet" to base of neck both Krika and Antroz are 27 modules high. Huh. Looks like Krika is pretty tall.
Don't count your squids before they hatch. With a five module neck, Krika should be far taller than Antroz with neck stretched vertically, right? Yes and no. It is impossible to stretch Krika's head to full vertical height on account of the orientation of his head joint. Thus, at most Krika is able to reach 29.5 modules in height, one half a module taller than Antroz (and this is assuming his leg joints are able to bend, which they aren't). As anyone knows, it's hard to make an exciting pose with any of your figures' legs stretched rigidly to their full length, so of course Krika is still bound to look very tall when posed next to your other BIONICLE sets. I'm not saying he's worthless for his height. But anyone who is of the belief that Krika is of some gargantuan form under which Tahu can get a decent amount of shade is in for disappointment.
"Tahu and Gali are too short / Onua is too tall"
The first one is a misconception, but the reasoning behind it is entirely accurate. How in the world can our formerly hunchbacked Earth Toa be the tallest of the Mistika? But Tahu and Gali are of no unusual height. Tahu, as mentioned before, shares his 25-module height with Hahli Mahri. Gali is merely one module shorter due to her creative but perhaps (depending on your opinion) out-of-place neck configuration. Onua, to my and others' regrets, is the aforementioned maximum Toa height of 27 modules. LEGO disappointed me quite a few times with his set, but this isn't the place to rant about that, only to present concrete facts about set height.
"Takanuva is too tall"
While I love tall Takanuva to pieces, for the purposes of my drawings keeping his proportion with other sets even nearly the same is inconceivable (remember I work in HSB). Av-Matoran under the energies of Karda Nui are taller than other Matoran, true, but not by too much. At most their height comes to 19 modules with legs outstretched (Source: Solek). The normal height for Matoran has remained pretty consistent since 2004 as 16 modules (story-wise, one bio). Thus, they are over 1/5th of the height of a normal Matoran due to Karda Nui's energies.
I do not mean in any way to imply that Toa and Matoran are due the same effect from Karda Nui's energies, or any energies that have as of yet remained unexplained. But Takanuva has grown from an assumed 26.5 modules of modern set height to 42 modules in height! He has therefore grown by almost a full bio, or 15.5 modules. Some might be apalled at this. I just find it an inconvenience that I will have to cope with in my drawings and in my fervent Takanuva/Gali shipper status (though after he leaves Karda Nui this will no longer matter so much). Certainly from a set standpoint the height is more than made up for by the creativity and beauty of the set.
And last, like the last not dealing with the Mistika themselves,
"Trinuma is definitely not 9 feet tall!"
Like the last, this is true. Trinuma in the set rises to 30 modules counting his horns, whereas 9 feet would be closer to 32 modules. I'm sure it's a height difference most people can live with. As with Takanuva, I'm impressed enough with Trinuma not to care.
I hope this entry has been enlightening, even if it does not change your opinions on the sets. I do not mean to change your opinions with this entry, although some of your opinions could in my eyes do well from a change. But I want to make sure that Mistika buyers know what they're getting when they purchase one of these new sets, and plan for the one they will truly enjoy most based on their own preferences.