I don't get it, what's wrong with the tourism mechanic? I made a city designed completely around tourism, works really well, I earn lots of money from it, my commercial zones make lots of money, my traffic isn't bad when tons of people are visiting since I planned for it and have lots of mass transit as well as road design that rushed tourists to where they want to go.
First of all, it's prone to bugs, like when they don't properly leave, and their numbers cycle endlessly.
The mechanics of how it works is also unclear to many players in terms of how does one attract greater numbers of tourists of a specific wealth class, and why certain figures fluctuate as they do. There is a disconnect between what a player thinks he's trying to do, and what is actually happening in-game. Why one day a city can have 1000 tourists come in through the rail station, and then the next day, only 30.
There really is no way to differentiate a specific "tourist" zone. Your best option is to build your roads in a way that forcibly funnel the tourists to specific locations, due to the stupid AI pathfinding. As such, your commercial zones further away from the city can actually distract from your landmarks and casinos' profit. This is one of the reasons why so many people lose money when they try gambling specialization.
Having commercial zones have both "goods" and "souvenirs" for sale is dumb and redundant. It leads to the commercial zones sometimes telling you "we have no shoppers" and that the" tourists are great for business" simultaneously. Shoppers and tourists should both just purchase goods and not have it be more complicated. I see no reason that positively impacts gameplay why commercial zones should sell souvenirs.
They also turn into hotels quite randomly. Hotels near your landmarks and casinos is great, but hotels in your residential community area causes undue traffic, and the local shoppers lose a place to shop.
The way the game works right now, casinos, landmarks, and commercial zones cannibalize sales off of each other too much, when they should work together. One would assume that the casino and trade specializations work hand in hand along with commercial sales, when they actually don't. There should be a balancing game in place, and a system of attracting tourists and adequately meeting demand with systems that work synergystically to fulfill that need.
I guess it's mainly a casino problem, really.
It's not so bad with just landmarks and commercial, and that
does have some synergy in the current game. However, once casinos are added into the picture, prepare for the casinos to eat heavy losses if you don't have enough tourists to satisfy all three adequately.