In the case of the Tarakava, the lower jaw is too long. They already looked pretty fugly in the face area in the original set, but at least the mask and the claws were roughly the same size. Here, it doesn't really look coherent as a head.
I don't really know how else to offer improvements other than just "use a different piece" or "make the masks bigger" or just "build it differently", I'm not much of a builder. I just see what I see, and I think they would benefit from deviating from the base design so that they don't look as blocky, stilted and lifeless as they do now.
Yes, that was a bit much,
As was this.
All I was really trying to say was if you're just going to try and remake the figures in their entirety, flaws and all, just in system where the parts are less specialized for the purpose and make them quite chunky and visually inconsistent (to me anyway), why not just enjoy the original sets themselves? I understand that obviously there are things that can be done with these figures, just that the figures would probably be better off if they tried to be their own thing rather than a shadow of the past.
I apologize if I came off as unnecessarily aggressive or insensitive, I just get a bit caught up in the process of stating my case that I don't really think about how that might make the other person feel.