Before going any further I must state that any camera model could be used as a “professional” device as long it help you to earn money from your clientele. So don’t be move about the following (very personal) suggestions. I am the first to proclaim that a camera choice is at the end a purely subjective choice as long the model you have preferred can fulfil your expectations in convenience and result.
The elusive Fujifilm GFX-Series…
So now I can felt free to entertain you about the “pro” questioning over the Fujifilm X-Series. First we have to agree for the stellar quality image output generated by the Fujifilm GFX Series system. This beautiful system like most medium formats proposed by the manufacturers is not really suited in many action photography situations that will need constant, rapid and extended facility to perform well even in very adverse contexts. So I will classify the Fujifilm GFX system as a fairly niche (and expensive) product that is asking more careful attention and is obviously less flexible in term of handling and transportation. But surely for people that are working with studio requirement (inside or outside) the Fujifilm GFX system will fulfill the bill (and empty your pocket!).
Now going through the Fujifilm X-Series system the is a lot of candidate to consider. If you apply the Weather-Resistant (WR) criteria as a priority you will finish with three evident contenders: the Fujifilm X-Pro2, the Fujifilm X-H1 and the Fujifilm X-T3. We know that the most recent one, X-T3, got the most up-to-date best reactive autofocus functionality and an extended video capacity. We know also that the X-H1 is the only one doted with an internal image sensor stabilization. And finally we know that the rangefinder style X-Pro2 is the only model with a traditional optical viewfinder and the electronic viewfinder option (EVF).
The Fujifilm X-H1 and X-T3 have both the possibility to add a vertical power unit that will translate in a better vertical handling and a much greater battery autonomy. These have the other advantage to have a centered EVF (same optical axis of the taking lenses) that assure you easier following or panning of your subject movement. Sport, nature or action photographers should be well served with the X-H1 and X-T3 no question about it. The Fujifilm X-Pro2 is a great reporter camera model for street and spontaneous photography. The optical viewfinder give an instant view of your subject without any kind of time lag between your naked eye and the camera viewfinder. This is a very unique feature of the X-Pro2 but I must add that I have learned that many of its users are preferring almost exclusively the EVF option.
When you are choosing a camera system it is better to look first at the optical offer of that manufacturer because you may need specific lenses for special applications of your own. In my sens the Fujinon line-up can respond to a good number of those specialized tasks. But some choices may induce some better choice of camera model. To give a good example lets take the case of earning the Fujinon “Pro” XF16-55mm F2.8R LM WR which is a very versatile lens for photo reportage and many other situations such as wedding. The XF16-55mm F2.8 have no optical in-board stabilization and that omission may be seen as a flaw for a trans-standard zoom lens. In that case the recommandation should be to combine the Fujifilm X-H1 camera body already equipped with the sensor stabilization option. So your lens choice can be paramount to the camera body selection.
As a personal general rule of thumb I am suggesting most of the time to select a second camera body identical to the first one. That way you facilite the overall manipulation of the two cameras that are owning the same ergonomic, the same sensor, the same interface and are using the same accessories including the battery packs. A third camera body could be a different model for different applications or specific contextual uses. For example two Fujifilm X-Ts twin models alongside a Fujifilm X-Pro for a more discrete mandate.
So what would be my personal choice
if I was still a corporate press photographer like I use to do a some (!) years ago? For the camera body I will probably select two Fujifilm X-H1 alongside with a Fujifilm X-Pro2. For the X-Ts lenses, the Fujinon XF16-55mm F2.8, XF50-140mm F2.8 and XF8-16mm F2.8 all WR are the obvious but expensive choice. For the X-Pros applications, the Fujinon XF23mm F2 WR, XF60mm F2.4 Macro and XF90mm F2 WR could be a sensitive choice. But all that is very relative and questionable for other photographers. But all those products are top of their line (except for the special purpose lens XF60mm F2.4 Macro) and are well protected from adverse condition encounters.
You may ask you why most of the professional photographers are loaded with a big chunk of photo equipment? Part of the answer can be the fact they don’t use all that stuff at the same time but they want to be prepared for every eventualities. Many in the profession are tempting to get rid of the weight and the overcrowding of all those expensive pieces of material. Some will select only a main camera body coupled with a more light version as a backup and complete the kit with two or three lenses. For special assignment they will rely on renting a more spefific lens or camera body. Others photographers are working on very specialized picture production and they only need few pieces of equipment to fulfill their task.
Many Fujifilm competent photo equipments are offered into their line-up and you shouldn’t be afraid to use them professionally speaking. Smaller and lighter devices may improve your photo creativity and mobility and ultimately serve your “pro” and artist expression. You don’t have to follow guideline that can only mismatch you (and empty your wallet!). For example Fujifilm products like the X-T20 or the X-E3 combine with lenses such as the XF-18-55mm F2.8-4R LM OIS or the WF23mm F2R WR are perfect equipment (but you will have to observe a little more care when you use them in adverse conditions).
As I said earlier there is no magic solution to propose for all the photographers. But we have to rely on our camera and lenses and master them in order to produce a “Pro” level of pictures that will be cherished by our customers who really don’t care about what is in our gadget bag…