The people working on the prequels had created a lot of fantastic practical effects aliens of all shapes and sizes, only occasionally spruced up with CGI.
We loved those.
It's not the effect, it's what you do with it. There's nothing about CGI that makes the aliens' accent offensive, and that was a problem both practical (Neimoidians) and CGI aliens (Gungans) in The Phantom Menace had. The non-speaking background aliens looked fantastic and they were sometimes practical, sometimes CGI.
In my opinion, the problems of that movie lie in aimless direction and post-production, not in the effects work itself.