I didn't go through all of the suggestions, since there's 140+, but I've got a couple of ideas to make the money in game mean more to the player than just making better weapons to then get more money.
I wouldn't be surprised if this had been suggested already, but I think there should be more levels of grips and guards. For guards maybe add some things that look like THIS or THIS. I also think fancy grips should cost more since by default when I start out I use them for everything to the point there's either no point or the other ones, or no point for the fancy ones.
I think there should be upgrades to certain elements of the shop. Maybe upgrades to the forge so it smelts faster, upgrades to the anvil to allow for different heads, upgrades to the shop front to entice richer customers (see next suggestion), and upgrades to the inside of the shop like chairs to make customers sit down and wait longer for the item, which would be necessary later in the game if you don't like to rush.
Another idea that should go along with both the last one and the next one, is a grinder/sharpener. You'd be able to buy and upgrade a sharpener to sharpen blades. The sharper the better, meaning the happier the client and more they're willing to pay. Also a higher rating which I get into on my last suggestion.
I think there should be different levels of wealth for clients. Perhaps they come in with a budget or wearing a certain level of clothing, like royal robes for people that are very rich, and burlap for people that just want a bronze dagger. It's kind of easy right now to just server customers with the richest of metals to keep making the most money. This also kind of segways into my next and final suggestion.
I think a cool way to have a popular shop would be with ratings. Obviously in the age we're set in people aren't posting on Yelp with a review and a 5 star rating, but people would talk about it. If it's a really nice blade people would want to come get their own from you.
This would also combat people just skipping lower tiered customers because they'll get a bad rating. There could also be upgrades to your shop to help with rating, like posting signs around town, making your house look better, and things like that.
Obviously I know this stuff will take a while, but I figured I've got stuff in my brain, may as well share it! :)
tl;dr
More grips and guards
Upgrade things in shop
Add a sharpener
Classes of customers
Rating/popularity for the shop