Keep in mind that Gregs official wording was that they all were about the same rough height so things like Onua and Pohatu being shorter than the rest can still be canon and probably is. What we don’t know is which of the Inika or Mata is the canon scale. Or if we should even use the toys to measure scale at all?
With that being said I do feel like overlooking the toys mainly because they have weird scaling is silly (Not to be disrespectful, I have a pretty good rational here so please hear me out.).
While the scaling of the sets are of the scales(I’ll stop, sorry) the proportions aren’t I think its important to make the destinction that while most Bionicle are humanoid they are not humans , they are an alien race built in the image of another alien race and because of that features it own range of proportions. Note: not all species have the same proportions but cases like the toa have unified proportions through out with minor exceptions for one or two contest winners even though proper scale is not present. Something I clearly don’t want is a Brutaka sized toa figure to be canon because we don’t need to mess with the scale more than the toys already have, I don’t necessarily think it needs to be enforced however.
Either way as a tip to everyone I do encourage visually analyzing the sets for inspiration because it will certainly help you hit that golden spot of looking like it belongs in G1. There are subtle things designers constantly do while designing products for a brand, like including repeating patterns or design elements between their products. Look at Apple for example, while not sharing the base shape their macbook has more incommon in design with the Ipad and Iphone than you may realize at first glance.
So since Bionicle was a sub brand of LEGO and Technic there is bound to be similarities in the design of sets as well as in parts to find.
I feel like I’ve gone on for long enough now, also have a tedtalk about visual literacy that I find really interesting. By all means let the creative juices flow.
Also once again I definately don’t have anything against what you said @ToaMagna just wanted to share some stuff to consider. I don’t think any of it should necessarily be considered for the rules but I think it should be in the back mind of creators at least.