Note that this game already had an English version (known simply as Might and Magic 2 - Gates to Another World) released in PAL territories back in the day. It looks and plays quite different to this one.
If I remember right that stats not changing happens even in the English version of the game. I definitely noticed differences in damage output when using different weapons.
I had a play of this for a few hours, and for all intents and purposes this version of the game is nigh identical to the English version except that it lacks the mini-map on screen and many of the NPCs you encounter don't look anywhere near as good as in the English version.
Differences from the English version of the game:
* No mini-map
* Graphically inferior to the English version. Wall textures aren't as good, interface looks worse.
* Very squished up item and equipment names (in the English version they are displayed in full)
* NPCs look completely different. This is neither a negative or positive.
* Combat is done better than in the English version.
* Enemies look completely different
* You now see portraits of all the party members on screen (this is more in-line with the PC entries in this game series)
* Doesn't have the insta-kill enemies present in the English version that would cause unavoidable death. This is a very positive difference.
* Dungeon maps go back to an unexplored if you leave and then return. In the English version what is explored stays that way.
* Doors are MUCH easier to unlock if you have robber/thief in your party than in the English version. Traps go off far less.
* Overall easier than the English version. Battles are easier, less damage from traps, you survive longer and die less.
Winner - English version. But this version does have it's own good points.
Screenshot of the English version:
And of the Japanese version: