I think you didn't quite read my post...
I never mention the term metalcore, in fact, I tend to hate most bands described with -core.
I even said that the improvement I was speaking about WAS NOT ABOUT TECHNIQUE (although nowadays people spend more time perfecting theirs, and that's completely positive).
If you're using the term close minded to describe me (since that was the impression I got) I think you're being somewhat hypocrite, since I am the one that's trying to çure people to the new stuff.
You can't be more close minded than not to listen to music just because it was released post 80's.
Despite this I agree with your last statment.
EDIT: And IMO I think Gojira's music has a lot more quality to it than Metallica's, not excluding the first albums. It uses structures that are a lot less primitive, repetitive and they actually are somewhat original.