That always bothered me in HF. I normally saw their helmets as their actual heads and not, y'know, helmets. The whole "mouth within a mouth" thing was always distracting to me as I knew that probably wasn't the intention of the set designers. It was taking set-accuracy too far IMO.
Okay, I know you said this over two weeks ago, but I have saw this and was highly confused. I know it's bandwagon for everyone to hate on TLR but not everything TLR did was bad and, in a lot of cases, the original trilogy was highly flawed as well.
The original trilogy was a lot like Spider-Man: TAS. I say that because in the show Spidey wasn't allowed to throw a punch because it was deemed "too violent." The first three films did the exact same thing. They had to use elemental powers but even then it wasn't used in their fullest potential, at least in my eyes. In TLR, you have actual sword fights.
Also, there's a difference between animation style and animation quality. Which style is better is subjective and a matter of personal taste. I, personally, prefer how things look in the originals. However, TLR's animation quality is clearly superior, though this is due to the film coming out 4 years later with better CGI technology.
Sorry that I kind of blew up there.