So after grinding commerce for years, I have come up with a number of things I'd like to see changed to the system in order for it to be more accessible to the entire player base, along with being more useful as a means to make money. Here's a list of what I think may help the commerce system as a whole:
1) Reset the value (demand) of items periodically, but regularly to a predetermined minimum value.
This would allow items to be sold at decent prices more consistently, it would be up to Nexon to balance how much they think players should be able to make within a certain time frame. This would also prevent larger servers from sabotaging their own prices for items by over selling a particular trade good. The trade goods should still gain value if they are not being sold (aka they are above the minimum you set), but if they are sold too much, every so often I would reset the price to some minimum amount. (You could do this every in game day, or even on a timer like the limited goods.) Either way, each good should be consistently worth some minimum amount in each town.
2) Please do NOT add any more of these pay to win enchantments into Commerce.
I am referring to the Trader, Trustworthy, and Haggler Enchantments, unless you add them into the pool of items you can buy with ducats, they will kill the market, even if you are resetting values. They make players feel like they cannot compete, if they don't have these frankly OP enchantments, because the prices have just shifted downward to accommodate them. What this allows players to do in internally destroy their competition, by forcing the prices so low that nobody that nobody can reasonably compete. I would suggest revamping the enchantments in some way, or adding them to the ducat shop. If neither of those sound reasonable, I would advocate for the enchantments to be discontinued or out right lose their discount effect. I am fine with commerce reforge gear because, it increases speed, but does not give players an exclusive value.
3) Add more areas to commerce.
If players have more areas to trade between, it will help level out how much competition occurs between each individual area. You have an entirely empty continent in Iria, and commerce would be fitting there. You could even create a commerce/exploration hybrid activity to do there, adding new types of mounts would be cool, and even having some sort of rare limited time, unlimited stock good may have players do commerce raids. There is plenty of potentially good expansions.
4) Potentially revamp prices/quantities to be channel wide, rather then server wide.
If players had to could spread out to different channels to commerce, you may see more activity. Like my first suggestion, if prices drop too quickly, which can happen if the prices/quantities are the same across a large server, then players won't make enough money to attempt to use the system. This might help larger servers deal with large groups trading all at once.
5) Fix the drop tables and ducat gain for outlaw hunting and bandits in general.
Adding in old blacksmith/tailoring manuals would be great, or giving the chests in outlaw homesteads more value may lead to more players doing this particular activity, but overall it would be cool to see a raid system implemented for outlaws. Players could party up and beat bosses, similar to field bosses, they would appear after stealing enough from players and it could be really cool. This point is not as important, but could also use some looking into.
6) Actively balance the commerce prices.
Mabinogi is an MMO, and there will no doubt be players who fine loopholes in the system and gain money far beyond what was intended, I would suggest the Nexon watches and adjust these commerce prices monthly, if not, weekly. Either way there should be more of a hands on management for commerce to make sure the system doesn't create problems for the market, but also does not become entirely meaningless for most players.
If you have any other ideas or critiques of my points, feel free to reply to this.