I have a decent[1] system with a dedicated center channel. Everybody complains that the mix is too loud if we tune for audible dialog on anything made in the past decade or so (MI3 bluray is fine, and I suspect that Transformers would be too).

1: Powered by a Denon AVR, not separates if you want to "No true cinephile" me.

I've always set up my center channel volume using the test mode (by ear many years ago, and more recently automatically with Yamaha's YPAO).

Am I meant to then override that by increasing the center channel volume so it's louder than the other speakers?

Or raise the system volume?

What really would solve the movie issue is there was more standardised sound across different streaming services. Every single seems to have a different volume and compression / setup.

That and having an industry standard way to crank the center channel (user setting) when downmixing to 2.1