It's extremely dynamic. The voice veers towards embodying an intimidating and menacing but yet almost brittle quality. It's still intensely dominating, and the inhuman quality also adds significantly, but the emotion of Hardy's performance still very clearly shows through. It's totally singular and unlike anything I think any of us have heard before, which lends a mysterious and sinister quality to it, making it far more memorable. The contradictions of it adds a lot to Bane as a character in ways I hadn't thought of from any of the photos shown.
So why are you crediting Chris for this? The voice was obviously all Hardy.
Because at minimum he approved of it and most likely had at least some
input. I don't know why I have to be telling you this, but directors have total creative control obviously, so he had to say "okay" and go with what's a very strange and ambitious (and some might say risky) choice. That's 100% assuming he didn't think of the general direction the voice would go anyway, especially since he didn't think Hardy would be available for the part for the longest time, so I think it's fair to say it's pretty likely he had some thought on where the voice would go.
Heath worked with
Chris on his portrayal of The Joker, and they were both mostly on the same page for the character to begin with. Heath would call Chris up, they'd talk for hours, and they'd work it through together. It goes without saying a massive part of that was Heath, but Chris played a large enough role to mention. So no, it wasn't 'obviously' all Hardy, in fact, there's nothing 'obvious' about that at all. If you disagree with someone to such an extent you think they're obviously
wrong, at least provide a rational argument.