Does anyone remember why Mad King Games decided to shift over to the sandbox / management gaming style? I mean, you already had a fairly hefty prologue and/or first chapter, totally AVN-style, and progressing through the story nicely. Then, out of nowhere, he says to himself, "I bet I could kill my game by shifting to a totally different playstyle!" Really, one of the worst decisions I've seen a developer make in a long time. Might as well have started with an action roleplaying game and then switch to a text-based choose-your-own adventure or something.
No idea.
And honestly, I'd say (and pretty much everybody would have agree with this) it was a huge mistake to transition into the RPG gameplay mechanic when the story was so heavily into VN mode.
On top of RPG initially becoming a really, really buggy error filled mess, it just slowed everything down, which ended up with dev putting the game "on hold", then later totally abandon it.
Honestly? I'd say even if the dev wanted to put RPG mechanics into the game, he really should have put that on backburner until the entire game itself was completed in VN mode.
Cause if the game itself was entirely done in VN mode and playable, noone would fault the dev for wanting to remake his game with a lot of RPG gameplay mechanics inserted (and perhaps he might plan it out a bit better, cause let's face it. It's not like the RPG stuff gets introduced in early game. It gets introduced very deep into the game, and all of a sudden and really sticks out like a sore thumb

).
And even if the RPG gameplay remake of Vis fails, players would still have the OG game in VN mode to get back to.
And this is especially evident given the dev didn't know what to do with the RPG mechanics and whole bunch of issues it was presenting when he implemented them into this game.
Either take more time to study how to make those gameplay mechanics, or hire someone else who is a specialist with a system that works.