Weapon proficiency (Dwarf)

[Jello!]

Making dwarves able to use light hammers and warhammers freely seems like it would make sense.

[Dhund]

Also, Dwarven Waraxes

[Egon the Monkey]

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.