My one real issue with the R1 Tarkin is that he was too expressive. Cushing’s performance in ANH was much more subtle so it therefore no longer felt like the same performance. Were it another actor, it’d be different - a different interpretation if you will. But because his face was realistically recreated, it made all of the grimacing and snarling and raised eyebrows that more off putting.
This right here. Cushing’s face barely moved in ANH; he emoted almost entirely with his eyes. Combine the more expressive facial animations with that weirdly smooth CGI motion and you get TarkinBot.
That said, Leia’s toothy grin weirded me out more.