The fundamental problem is obvious to anyone with functioning eyeballs. Animation allows for expressiveness, exaggeration and charm that simply doesn't translate to photorealistic CGI.
"Is Mission: Impossible - The Final Reckoning a disaster or a triumph? I genuinely enjoyed watching this picture, although I worried constantly during the first hour that we were in for a total shipwreck. (At least, until we got to the actual shipwreck.) That worry doesn't entirely dissipate during the second half. The whole enterprise reeks of Marvel-itis with its endless callbacks." -Bilge Ebiri, Vulture