[Fantomen]

Vanilla as is very unbalanced for multiplayer yes, CBM adresses that.

The changes are not arbitrary at all, but it takes lot's of multiplayer experience to understand why they were needed. It's admittedly a bit of a catch 22 there because you can no longer fully obtain that experience when all games already use CBM, you have to trust the veterans who came to these conclusions in the first place.

In the specific case of hammers, dwarven hammers were so good that it forced everyone to make them in order to compete in mp. Without dwarven hammers you lost, so every nation that did not have national earth magic had to take it on the pretender, this limited the number of viable pretender builds and thereby the number of strategies available.

This was not so much a balance adjustment as it was a way to diversify the strategic spectrum. Not only in the sense of pretender builds, but also because forging any item at all before you had your hammers made was wasteful playing, which really shaped the strategic options for competitive play.