This scares me. We don't know if he's talking only of the Japanese version or the US or both, and we don't know if he's changing the actors or if they're the same but are simply rerecording dialogue, but still. Twin Snakes had (mostly) the same actors redoing a new script, and while it was overall fine, there were some worse things to the new work compared to the original (Campbell and Naomi in particular). Besides, nothing in the entire collection needs new recording. The Metal Gear franchise boasts some of the best voice acting in the entire video game catalogue. Nothing needs to be reworked. What the hell Konami.
Maybe this is too soon to panic. Chances are that Kojima is simply adding stuff or making small changes to correct continuity errors or the like. I hope so.