I think any dwarf starting in Mithril Hall should be at least somewhat proficient with long spikes. Kinda like how some elven races start with proficiency in bows and double edged blades. It makes sense to me, since the culture there is strongly encouraged for the young dwarves to mine, craft etc.
Specifically to the point though beyond the opening statement. The soulhammer I see was reclassified at some point to long spikes instead of short spikes where I am pretty sure it was previously. That means a cleric of Moradin can't use the weapon he chooses to give his priests without spending a feat in weapon proficiency. Don't get me wrong, I absolutely love the change that was made to it from an earlier suggestion(thank you to who ever did that by the way, love being able to smelt and craft with it now).
So my two suggestions would be
1)grant either all dwarves, or just dwarves from mithril hall proficiency in long spikes
2) the holy symbol of moradin grants the proficiency/ entering the faith of moradin grants the proficiency.
Not sure what others think about this, just my 2 cents.
Dwarves from Mithril Hall/Clerics of Moradin
Re: Dwarves from Mithril Hall/Clerics of Moradin
Clerics of Moradin now have long spikes added to their skill list.
"A man may die yet still endure if his work enters the greater work, for time is carried upon a current of forgotten deeds, and events of great moment are but the culmination of a single carefully placed thought." - Chime of Eons