Of course, the traffic situation is a mess. Changing intersection movement cycles usually results in that situation, especially if it is implemented without warning or without advanced information as would have been the case if prior consultations were made. But this is not to say that the intervention is not effective. There is not enough information to make such conclusion. Most of the analyses and subsequent hypotheses are mere speculations. Transport, while influenced by human behavior, is a technical phenomenon, more science than art. That's why it has graduate studies leading to master and doctoral degrees.
If something is definitely certain, it is the fact that congestion in that "corridor" is getting worse. I placed the "corridor" in quotation because it has a specific meaning in transport science, though it doesn't need to be explained in depth. I think most people understand what that means in traffic terms. The other fuzzy phrase is "getting worse." Everybody knows what "getting worse" is, and, if we talk about traffic, it is always getting worse if we leave it as it is. The number of vehicles always increases; population grows and so does the economy, and the city and the country develops. It's an inevitable thing unless we go out of our way to find ways to make it better.
Our good friend, Mr. Enrique Peñalosa, always starts his speeches by saying that when cities develop, everything gets better, except transport, which often gets worse. And this is very common in developing countries. As the GDP grows, people buy cars, but transport infrastructure could not keep the pace. So congestion worsens. Most people will simply say, "build more roads!" or "expand the roads!" The experience in the last century proves that this is not the solution, but rather to focus on mobility and not congestion. This is the concept behind inclusive and sustainable mobility. Congestion is a symptom, not the problem.
Back to Ban-Tal, why is everybody not surprised? You have to get back to the phenomenon best explained by data existing at the city's planning office between 1994 to 2006. If we get newer data up to the present, it would probably be more conclusive. The bi-polar new town development of the 1980-era Metro Cebu Land Use and Transport Study happened in just one direction, the north. At the turn of the millennium, the end of the plan period, the population-employment continuum reached traffic generation levels. This was partly solved by the flyovers in the later part of the first decade. But that was not the permanent solution, as would the other proposed flyovers would be. Public mass transport is, but it takes time, and necessitates intermediate solutions.
The other complimentary but likewise temporary solution to address congestion, while public transportation is being improved is dezoning. It's unfortunate that it became politicized (even up to now) but really you have to ask the question, do you want to arrest congestion or not, even if it's only temporarily? The Ban-Tal corridor is reserved for public transportation and there is already a law which defines it as such and keeps it from being constricted. Of course, laws are just pieces of paper which need to be enforced, if there's a will to do so.
Disallowing left-turns is indeed a traffic intervention. How effective it will be is at most a mathematical concept and not anyone's opinion. Gov. Cuenco Ave. is a long stretch with plenty of intersections, and each has peculiar traffic movement cycles that are readily measurable. And it is measured regularly by CITOM's planning division. So it wouldn't have been difficult to present it to the public in support of a proposed intervention and ask the people's cooperation in "experimenting" it. CITOM doesn't experiment out of nowhere, there are data analyses which concludes a particular intervention based on empirical data and transportation science. The experiment validates those, especially the assumptions used.
At the end of the day, we go back to traffic congestion being a symptom and not a problem. That's why CITOM as a traffic "operations and management" agency can only offer medicine to cure the symptoms. What lies beneath is the inseparability of land use and transport. Why was the 1980 plan named MCLUTS in the first place? We have to understand - traffic management is not synonymous with transportation, and it surely is not with land use! If the city decides to forego the dezoning policy, then it should declare that (just allow me to say, Good luck!). And as far as "no left turns" is concerned, present the technical basis first, so it won't become one's opinion which will be supported or contested by other people's opinions, too. Who knows, it might be the right decision. But until that is ascertained, I can't even make any kind of opinion, because I don't have any basis.