It's pretty hard to believe what your saying, especially since most anime voice actors are absolutely terrible. And that includes both the original in Japanese and the English Dubs.

Protip: You don't always have to understand what someone is saying to know whether they are a bad actor or not.

No, no. You really don't.

I'm not the same anon who said that Japanese voice actors are mostly terrible.

It's just that he isn't wrong by virtue of not being able to understand Japanese.

Yes. If their delivery is in fact shit, then you should be able to tell even if you don't speak the language,

Delivery can be appraised independently from the precise meaning of what is being said.

Example: A common dramatic exercise for actors is to repeat the same word in lieu of an actual sentence (for example "Tuesday"), but to change the tone of their voice, the cadences, volume and such to alter the impression it imparts to the audience.