Blender used to get a lot of stick about it’s UI, but it’s now it’s doing amazingly well. It seams to be freeing 3D from Autodesk.
GIMP seams to be going through a bit of a development phase and after GTK3 move is complete, other features will get the that development. It could be interesting few years.
As for trying RISC OS, no where is especially active to be honest. Though it can be run on Raspberry Pi. The big thing it still does best is save dialogs. Just drag into a file manager window. For the decades after leaving RISC OS I have to copy paste directory paths like a primitive! The ROX Linux desktop gives you a bit of a taste of it, but only ROX apps have the dialog magic. Last I run RISC OS was ArcEmu to play Bug Hunter 1 & 2. I did some open source work on RPCEmu to run games I made as a kid. I should run it again to show the kids what I was doing at their age!
Mmm I know what you are saying but I used to work with a lot of 3D game artists. All but a few hated Blender and said they found it counter-intuitive. But really it was that it wasn’t just like 3DS Max and Maya (and it is a bit like Max to be honest). I’m delight over a decade later it’s use has ballooned anyway.
During the same time in games, they switch all the non-2D artists to GIMP to save money. Every time I went into the animation room for something, I could hear “GIMP can’t do X or Y” and every time I could show them how it could. They didn’t want to try and were confused/cross it wasn’t PS.