I am a bit divided on this matter. Yes, mass tourism is very damaging. But it takes such a role in the local economy, that some of the reactions we've seen lately look like a lot of ungratefulness. Like "we like your money, feel free to send it, but stay away"
I totally get it, you want to get rid of the bad affects of tourism in your city. But provoking guilt in individual tourists, who tend to be much less of a problem, that is no solution.
When it comes to holidays, I think positive motivation should work, such as promotion of individual tourism. Airbnb is actually very a very valuable tool in this, not a parasite on hotels, cities should find a way to use this new kind of service instead of fighting it. Or promoting visits all over the year. For example making different taxes per night (common in some countries) depending on the month of the year. Or museums and monuments could have different prices too.
The bans and limits should go to the source of problems. To huge travel agencies, to the enormous ships, that just flood a city with thousands of people, who won't contribute to the economy too much (they spend mostly on the ship). The large crowds of tourists are horrible.
I've always wondered, why there is no upper limit on the tourist groups. You know, when you want to put something outside in a public place (a street, a place), you ask for permission and pay for it (typical examples are restaurants in the summer, or events like concerts). When you organise any gathering in public places, you ask the local authorities, or at least announce it (depends on the kind of gathering. But even if it is one falling under the basic right to gather, they can tell you no should two large gatherings want the same spot at the same moment). But the tourists can go around in groups of 30-50 people. And that is problem in many places. Several such groups at a time can destroy a place. Even one is annoying.
This article is well intentioned. And better than most about the subject. But useless, because the people likely to open it are already considering various alternatives.
Valencia is a great place to visit, sure. But there are many reasons to see Barcelona. Or try to tell the tourists "oh, just try Reims instead of Paris, it is nice too".
What surprised me in the article: advice like "put down the selfie stick". Really, this should be a no brainer. Actually, the selfie sticks are a good example of a negative phenomenon that can be very easily addressed, and where a kind of prohibition or limit could work.