I agree it's a huge overreaction, especially if the game is doing well in western markets. People are comparing it to FF13 which was average, but did very well, but the problem with that was people were unaware / didn't believe it / or just flat out bought 13 anyway and once they played it had a bad taste in their mouth. And instead of Square fixing it with a new game, they took the easy route and made 2 more sequels.
It wasn't just FF13, it was the sequels as well sales tanked after that.
FF13 : 1.5m JP week 1
FF13-2: 540k JP week 1
FF13-3: 285k JP week 1
FF15: 690k week 1
If anything this is a huge gain from were the franchise was headed.
FF15 has sold more in it's first week than FF 13-3 has sold in it's lifetime already in JP, and by next week it should also pass 13-2 lifetime sales in JP as well.
People are just trying to bash 15 by comparing it directly to 13 sales, but there was a ton of hype for 13 until the actual game came out. Week 1 numbers were huge, but the drop off afterwards was incredibly hard.
See if the same happens to FF 15.
FF 13-2 struggled to break 1m global in week 1 sales. FF 13-3 struggled to break 1m global in lifetime sales.
So yeah there was a huge decline beforehand.