As the suggestion says, I think any concept tied to Appraise would benefit a lot from its effectiveness being dramatically increased. When the point gets to levels such as 15+, I think it should offer steep, steep discounts from notable stores such as Voiced buying waters, or buying potions from the Souk so that even non-brewers could make a business out of re-selling them.
The economy of EFU V6 is, as it stands, cool when it comes to discussing it such as the importance of water, but when it comes to water itself, people would rather (understandably) use it themselves than sell it. Only a few that could be counted on one hand have decided to act as peddlers of water, and beyond the roleplay, there is little incentive to be a water merchant.
Not all water merchants will be philanthropists doing it for a good reason. John Syter made his fortune from it, why is it so hard for other up and coming merchants to do the same? It should be the go to reason for aspiring Voiced with an eye for business to chase the value of Ephian water, but it doesn't feel this way IG.
That's the main reason for my suggestion, but beyond that I think it would be cool for Appraise to impact prices more in stalls. I very much dislike that the player economy from the time I've joined EFU to now (from late V4 to now) has always been dependent on finding and selling found loot in quests, whereas every other aspect has to be imagined. Imagination is fun, but I think we would see a lot more merchants if it wasn't the same dull routine every merchant and some strategy and fun could be involved in it.
It could probably also do with being a class skill for everyone, like for the other social skills, at that point.
I think there's something there, but only if decisions other than Taxes could have a big impact on store prices. If e.g. the presence of a lot of corruption (Jannies pocketing fines, people doing Brooking) etc jacked up the store prices like a tax rise did? Then we'd have interesting PC merchants because they'd be a source of conflict for people doing Shady Things. Otherwise it's just a smooth circuit of 'ask for low taxes, sell cheap potions, no risk'
Definitely, I think that making Merchant Lord just way better at reselling things would be more active and interesting than a wage, for example.