is it bad things if he switch to VXAce? or it because XP much harder to work with? i'm not familiar with RPG Maker.
Full disclosure, I'm not very familiar with the 'lore' behind this game's development (past that it's been years since a proper update).
You can make a good game on any of the RPG Maker versions, though the community tends to gravitate towards whichever version is the newest, since that will receive the most support. On that note, the shift to the newer VXAce is understandable, since VXAce allows for custom formulas, but if they were going to swap systems, I personally would have just gone to the new
est version, MZ. The frustration of this really comes in because making such a huge decision as changing which program to run the game on means that on top of normal development time, everything that was already finished will now have to be ported over.
Again, if he was going to change, I think it would have been wiser to just modernize it into MZ (or at least MV), since that has the best support, is pretty user friendly, has quite a lot of community-made plugins and assets (even more if you combine the fact that you can pretty much use anything from MV in MZ, meaning that grandfathered plugins and assets are still usable).
As a quick side note, for people going into RPG Maker for the first time, or just casually, MV is a lot more affordable. Anyways.
I've met several dedicated advocates for the older programs, I've always thought the the newest MV/MZ is the way to go. Regardless, like I said, they can make a good game on really any of the provided programs. They just need to... you know...
make it.