Hensei Series changes, why were they done?

Because in Godzilla vs king ghidorah, He was changed and got even more irradiated. They were trying to be realistic and they changed his roar, I think the heisei roar is by far better than the 84 one. And Godzillas late heisei appearence is the best of all the original Godzillas.

Technically, the Godzilla in '84 and '89 WAS the same one that appeared later in the Heisei movies. The explanation is that the one that showed up in the 80s was created as a result of what was shown in '91 in GvKG, that it was a second Godzilla mutated from the Godzillasaurus on Lagos Island, and NOT the original, in fact.

Well I'm assuming it has a lot to do with the fact the suit actor had a horrible time with the 84 suit with it being extremely heavy and not fitting him. So with the idea they needed to make a new suit anyway they slightly changed the design as almost every Godzilla movie prior and after has done. Since the Biogoji suit is my favorite I've looked up info on it and apparently they felt he needed to convey power better, and then the gead was made more felinelike I guess just on the opinion it looked better whick I think most of us will agree it did.

Alas I still cannot edit my posts. Oh well, the "gead" I put in the other post was supposed to be head.

Aside from the as for the roar, there are a lot of theories why it's changed, but I think the one I agree with the most is that if you look back the 84 and 89 Godzillas are somewhat darker than the later heisei movies so maybe they didn't want the roar to sound as menacing. Maybe They felt the new roar better woked with Godzill'a new size. I don't think toho's ever given an official answer so it's all speculation