Smiths should sell more arrows at a time compared to the amount they sell now. The base stock should be 500 arrows.
Details/background on your proposal
Currently, all Smiths stock up to 40 arrows at a time. Considering how fast a bow user would go through 40 arrows, this is definitely not sufficient and chest farming would net more than a Smith’s entire stock of arrows in just 10 minutes. Besides, the stock for the respective Smith is shared for the whole server, so if there were multiple bow users in the server, there would definitely not be enough arrows to go around with a single Smith.
Reason to add/change
Because Fish Bait is already sold in high quantities by Fishmongers, it would make sense for a bulk item like Arrows to be sold en masse rather than in a quantity comparable to common items.