The only thing i dont like about the trader roads is their routing logic, it can be bloody terrible sometimes.

In my Rome game i have a section of my empire with 4 !! roads running parallel with each other. They need to bias towards existing routes rather than absolute minimum distance. Of course if the route doesn't run through the city you dont get the trading post, so it is infuriating when you plop a city as Rome and the road goes next to the city, not through it, or rather than go through cities in a line it will just bypass them and make its own road. Unless you plop your cities in perfectly square grids it can be a nightmare to get it to work properly.
Although as Rome it is Bloody annoying it also affects other CIvs as well with foreign trade. You know sometimes when you trying to trade with a city that is <than 15 tiles from your nearest trade post but it is not available !??. Likely because the routing logic doesn't go through your Trade Post city, thus being out of range. The Trade Post system is great but the road routing logic just shoots itself in a foot time and time again.
You wanna see Road spaghetti,.....Play as Rome on a map with growing room.... Forward settle like a madman and then back-settle

...... and behold. the ugliest road system you have ever seen.

I was kinda OCD in regards to roads in Civ5, Making sure only 3 roads entered or exited a city at anyone time(with gap either side).....minimising t-intersections and when you can hide them in tile improvements where possible etc, even when it costs an extra tiles to make sure it looked nice.... I miss this.....Civ6 roads are the devil