Right now, dwarves can worship many other gods at once and it creates bothersome backlogs of bugs to juggle them all and a drain on dwarf manpower to find non-utterly devoted dwarves that should have joined a covenant many moons ago.
I believe a restriction would be both better for the game & still consistent with roleplay in the archaic way, it doesn't denote that there isn't a pantheon of gods dwarves believe in but rather that for their own reasons its easier for individuals, families & civilisations to focus on single gods as ones they treasure for certain reason.
- Each dwarf would choose a patron god off their highest sphere, then split that between their family and other ties like civilisation where present, meaning in certain hillocks you may find a majority religion of ardent "Uzmosh the light of Torching" and in another a completely different cult from the same pantheon or a more colloquially wider and broader civilisation wide dwarf religion, perhaps worshipping a god of the earth, gems & fortresses (all things dwarves like very much)
- This leaves dwarves open to conversion applied by other civilisations where nessecary, especially if the region is a sphere that is polarised, like water & fire that are hostile to one another in a more straightfoward way. Patron gods does not diminish the dwarves appreciation of a sphere as much as let it be known who's your #1 with enough forceful or self applied dedication, it may change.
- Civilisations with very little religious faith may to much surprise end up being secular with no particular stance on religion and no official state religion upon the land leaving many towns either godless or few religious minority worshippers to apply the effects the entity can have on its civilians
From a game perspective worshipping 1 god is a lot more of a easier need to manage, it doesn't exclude gods from the story of world-generation and opens up a lot more interactions with a lot less opposition for internal clashing. In many ways religion would become like the features of the dwarves themselves, at times variable traits between them being distinguishable but all the same, like one with auburn hair and high cheekbones and another civilisation with coppery skin and jade green eyes.