The X-Pro3's unique design has me really excited for the X-H2. FujiRumors near constant insistence that the X-H2 *might* not be coming in 2020 leads me to a few wild speculations:
They're going for something completely different with the X-H2, it seems obvious to just make an X-H1 with the updated X-Trans4/X-Processor4 tech, if that was the plan FR sources could be more definitive on release timeline than just "eh, maybe 2020, maybe not."
The uncertainty in my mind means they don't yet know the full design/tech of the camera. Maybe they're going for a more video oriented body with a new layout we've not yet even considered (ala X-Pro3's radical redesign), maybe (finger's crossed) they're waiting for X-Trans5 or X-Processor5 tech to be ready and skipping the X-T3's video tech entirely to come out with a major video upgrade and not just an X-T3 with IBIS (lovely as that sounds). It would make sense as their original goal with the X-H1 was to entice pro photographers to switch, however they screwed up because they used 2 year old tech in the process. Why do the same thing with X-H2? The X-Pro2 skipped the X-Trans2 sensor and was the first camera featuring the X-Trans3/X-ProcessorPro system and it was a massive success, still selling new units damn near 4 years later.
I know an X-T3 with IBIS/pro body sounds awesome but how much better would it be to have a totally unique new camera geared towards video the same way the X-Pro3 is geared towards Photography?
The only drawback I can see is we're probably looking at a late 2020/early 2021 release date in the best case scenario. I say it's worth the wait.