I've been a Desktop user for about 14 years. I have seen a lot of reasons that users are saying avoid ArcGIS Pro. Just thought I'd share my experience since I've quit ArcGIS for Desktop. I had played with Pro after going to the SE UC a few years back but didn't commit. I decided to change because my attribute updates to services hosted on ArcGIS Online decided not to save when editing in ArcMap. Tech support couldn't duplicate the issue on their end and couldn't figure out why it wouldn't work. On a whim I wanted to see if the same issue would happen in Pro. When I moved everything into a Pro project the edits to my online services worked as they should. Just as a point of info I don't develop or write scripts so I can't speak to how that works.
The biggest hurdle in migrating to pro is relearning where everything is. The interface has changed a lot, but thanks to google its pretty easy to find what you are looking for. Editing is a bit clunkier in my opinion than it is in Desktop. One suggestion I have would be to bring the snapping options back to the right click menu. Another issue is that so far there is still no fix for creating hyperlinks in the identify window. I brought this up about two years ago and as far as I can see, it seems like it still hasn't been addressed. The last negative I have is that labeling is a bit slower but its really a minor inconvenience.
Pro does make it much easier to work with those items that are hosted on portal and ArcGIS Online. My organization has made a heavy commitment to Online and it has definitely made my maintenance for the hosted services much more convenient. The ability to create multiple layouts in a single project is also a big plus. I've seen some worry about the lack of ArcCatalog. You use the Project Pane in Pro. It works essentially the same as the catalog window in an mxd but with some added functionality. So it's pretty much ArcCatalog its just not available as a standalone program.
ESRI can deny it all they want, but the bottom line is this is going to replace Desktop. Maybe not this year, but eventually it will. Overall I'd say I'm happy with the switch. Once I become more familiar with the interface I don't expect it will feel much different than Desktop did. I'd recommend that users start becoming familiar with this program.