You should always start with doctrine. Unless you should not.
I have had a chance to hear a couple of times that Wardley Mapping Doctrine is the simplest way to start your adventure with strategic thinking in your organisation. This line of thought is not unjustified.
Usually, it is not the mapping that holds people back. It is the insufficient understanding of their domain and business, which results in proposals that are unacceptable for some stakeholders. I do not even recall how many such proposals I have created in my history, and I am very thankful for the iterative nature of strategy, and that I got second chances :).
Doctrine is much safer to start. Just look at the table below - it needs almost no explanation to be useful:
You do not need to convince anyone that people in the organisation should be able to talk to each other and have a shared vocabulary. Everyone will agree that knowing your users is a good thing. Of course, the devil is in the details, because raising the point of f.e. common language requires pointing out situations which did not work in an organisation, and this is a political move, and it can backfire.
If your organisation is big enough, you will threaten somebody's power by pointing out things that do not work according to doctrine. There are two ways to solve it:
the political game through finding people that can gain thanks to the particular practice, and building alliances.
starting with yourself
The latter means that you do not have to stick your neck out and that you can learn on your own mistakes. If it works, then it is great. If it does not - nobody sees. (But, please, let me know if things do not work for you, I want to learn more about those types of situations). For me, personally, politics is the tool of last resort, and I use it only if I can get things done in any other way, for example because the root of the problem is beyond my control.
This segways me into the merit of this post. Starting with doctrine is valuable, yet I barely mention doctrine in my workshops. The rationale for that is quite simple - there are peaceful times in business during which you should be building your form, just as in real life. And this means following some sort of doctrine. And there are situations where you need to execute the best of you, with everything that you have got. There is no time to practice, very little time to do research... you just buy time to be able to focus on the doctrine later. In other words, sometimes, the lack of fitness is not your biggest problem :).
But if you have some market and working business - do focus on doctrine. It is the easiest start into mapping.