You have probably heard some Agilist criticizing "Waterfall". Common place for many agile texts and that in my humble opinion, is one of the biggest delays for the mindset change so advocated by these professionals. That's why I listed 4 major mistakes made by these agility colonizers.
1- Waterfall only delivers value at the end of the project
Waterfall is a pejorative term, so much so that some practices such as Disciplined Agile have already abandoned it, preferring to refer to predictive practices as "Serial".
The idea of the "Waterfall" is that each phase flows into the next, and the real value is only seen at the end of the method. Basically, value is only perceived at the end of the production process.
It is not only pejorative, but also incorrect, criticism is given to the visual that practices such as the Gantt chart or the CMP - critical chain method - visualize the workflow.
In theory there is no value in having the result only at the end of the project, but in practice there are "N" variables to consider, and perhaps knowing your production flow at the beginning of the project is already, in itself, a value delivery. Such logic applies to industrial reality, but not necessarily to technology reality, and this is where many agilists fail.
2 - Agility as a silver bullet
Agility was a response from the Technology world to the constantly changing environment surrounding software development, and to the way of management in place until then, which was predominantly from industrial and construction areas.
The answer is very welcome, and is a necessary change for any project management for the 21st century, but it is not the only one.
3 - The one-hammer specialist
Understanding the practice of project management requires understanding how to apply it in the most diverse contexts, although agility is something that is here to stay, it is unwise to believe that it alone is a silver bullet.
An example that Américo Pinto uses a lot when talking about PMO is the one-hammer specialist, that person who keeps looking for nails, even if the situation calls for a screwdriver.
And this is what many agilists do, they get a Scrum certification and start preaching agility, when they have never even met the project environment.
That's why it's important to remember that certifications form experts in practices - not in project management - Managing projects requires practice, with different contexts and scenarios, and that takes time.
4 - Agility for agility's sake
The problem is that today we live in an environment of "Agile Colonization" preaching a change of mentality, without even knowing the current mentality. How do you tell someone who has been practicing for 30 years a practice that works that they need to change?
Agility for agility's sake is not a justification, nobody changes because it is fashionable. Change is necessary when we begin to face volatile and uncertain environments where tomorrow may be totally the opposite of today.
It's about responding to context, to change. To do more with less, to deliver more value and less bureaucracy, these are indeed justifications, but to do so requires analysis, understanding of the current scenario, and options to choose from.
The truth is that no practice is stable or immutable, and we should celebrate that even predictive practices are beginning to put adaptation as their foundation, because as long as we flail around, we will not be complete professionals.