If you have a team of people with stagecraft experience and good audio equipment, you'll have a better shot of success than most amateur RPG makers.
I think VA can enhance a game quite a bit. It's just something that's hard to get right; there's a medley of things that could go wrong to make it distracting or not worth the effort:
1. The voice actors don't have the same vision of the scene taking place in the game, leading to awkward delivery
2. The conversations lack chemistry, due to voice actors not knowing each other or recording their lines at separate times and places
3. The voice actors are talented but don't know a lot about video games and the kinds of scenarios that can take place, leading an inadequate understanding of the scene
4. The voice actors know a lot about video games but aren't very talented at voice acting
5. Audio equipment is inadequate, resulting in bad sound quality
6. The timing/intonation doesn't match the facial expressions or body language of the characters, making the characters seem like off-kilter puppets or robots, or else that the voice doesn't truly belong to them
7. The on-screen text doesn't flow at the same pace as a natural conversation, resulting in awkward or stilted conversations
8. The dialog isn't very interesting in the first place, and it takes too long to listen to the voice acting for it, resulting in players just skipping the voice acting anyway or feeling frustrated if they can't
9. The voice acting, even if technically good, doesn't quite match the creator and/or players' vision for the character
10. Voice acting done in other languages than the native language in which the game was made (e.g., English language track for a game originally released in Japan or vice-versa) can make characters feel different than how they feel in their native language
11. Repeated lines (such as chatter in battles) are too repetitive or annoying
12. The volume of the voice acting is too loud or too quiet compared to the music volume and sound effects
13. The voice acting is too melodramatic, overacted, or cheesy, resulting in "
Narm," moments that are unintentionally funny when they're supposed to be serious
Etc., etc.