I worked with some really, really good directors and actors, but there's a limit to what they can do. The biggest constraint is the need for perfect mouth flap syncing. The original Japanese versions aren't even very well synced, but English-speaking audiences apparently demand it. It really constrains what you can do with a performance.
Emotional explosions that are great in Japanese seem really cheesy when done in English. Since Japanese syllables almost always end in a vowel, you get these really big month flaps that are hard to work with. In really bad dubs, it's why you get lines like "Heyyy! What's the big ideaaaa!" so often.
Of course, dubs usually have a tiny budget as well. That means that there's only one actor in the studio at a time, so they never get to play off of each other.