It may seem strange, but a lot depends on the voice acting, I hope it will be at the level, as, for example, happened with Starcraft Brood War. And you will not call any non-professional bloggers like an orc podcaster for voice acting.
The voice acting is still using the original recordings, if i am not horribly mistaken. So why would the voice acting be a problem?
They said it would be available in more languages I thought in the deep dive so ignorantly I’ll say the Russian choice is new and he is concerned about the voice acting…although are all the voices being done or just text.
You are correct, original D2 had these languages (according to the official webpage):
Available Languages
English (US)
English (EU)
Español (EU)
Français
Italiano
Polski
한국어
While the resurrected version has:
Available Languages
English (US)
Español (AL)
Português (BR)
English (EU)
Deutsch
Español (EU)
Français
Italiano
Polski
Русский
한국어
繁體中文
日本語
What? No pig latin? 
They also forgot about Esperanto.
But regarding the topic, the important part might be this:
@HandsomeJack maybe we need to double-check whether they meant voice acting or “just” text translation.
If they get a grizzled Russian accent in Russian it would probably sound menacing being asked to stay awhile and listen.
Blizzard only uses union voice actors these days, as far as I understand. There was some labor related drama around 2016 after which they changed it.
Interesting and understandable, only issue upcoming to voice actors, stuntpeople and eventually actors is computer generated versions will become passable and cheaper. Going to be interesting how they battle that one.