It doesn't matter how much of a hack any actor is, it's an order of magnitude more hacky when the soundtrack is dubbed into another language.

He does have a certain unique style that is all Arnie. "I'll be back" just does not carry the same impact when done in a non-Arnie voice.

He might not hit many notes, but he hits them damn well. "Get down!" "Get down again!"

He has a very unique manner of speech. Pretty much any significant actor does. Localized dubs lose all that.

Schwarzenegger without the thick Austrian accent isn't Schwarzenegger.