Making dwarves able to use light hammers and warhammers freely seems like it would make sense.
Also, Dwarven Waraxes
That would be absurdly good for Clerics, Sorcerers and Bards, as it's basically free Martial Proficiency. If you want a 2-handed weapon, /c two_handed a Waraxe!
Giving Dwarves Light Hammer would IMO do for "thematic cultural weapon" without giving another free feat to a race that gets a lot of combat bonuses.