Not a comment on the voice acting in this show per se, but some observations on voice acting in general.
In many ways voice work is harder than regular acting because everything has to be communicated through the voice, and that isn't just inflection. What a lot of people forget is that when you are moving around you get out of breath, and you talk differently. Moving also effects the way your voice sounds.
Orson Welles understood this. When he was rerecording dialog for the sleigh ride scenes in The Magnificent Ambersons
he sat the actors on the end of a board and he sat on the other end and bounced them
to get the correct shake in their voices.
I had the rare privilege of directing a bunch of name voice actors for a video game around xmas 2000, including Jim Cummings, Billy West, and Janet Waldo, and it was interesting to see how often they would stand and ACT as opposed to just sitting on a stool and read their lines.
In fact, and a worthwhile story to tell, initially Janet Waldo was having problems getting the voice of Penelope Pitstop right (a role she originated). The line was simply "Bye, y'all!" but it didn't sound right. At first we worried she couldn't do the voice any more after 30 years, but, finally, I told her from the booth, "Janet, you're not saying, 'bye bye', you're actually saying 'eat my dust' as you blast by them." Well, on the very next take she swung her arm in a dismissive wave and called out, "Bye, y'all!"
in exactly the right way. The voice was there! The voice came back precisely because she was ACTING and not READING.