Thanks for the tip on Ctrl+Shift+A, I completely missed that one!
And yay, I’m glad you think some of these suggestions are good!
I’d rather see it as an preference option in the editor rather than depending on another option, so that people whose layer/group setups make sense with this can enable it. Enabling Highlight Current Layer with H is about as much trouble as hiding the meddlesome groups, at least for me.
Finally, regarding the tileset image change of width (changing height doesn’t need updates to maps), my goal here is to change the tileset definition such that existing tile IDs are not affected.
I like the extra capabilities offered by this option, but I think it should be a new Tileset type (“Spritesheet”?), instead of replacing the current basic tileset. Though you say it shouldn’t be hard to update for, it’s still an unnecessary hassle. I also think the current style is very convenient and simple to work with in engine code, and worth keeping around just for that. I’d give up all ability to auto-update maps on resize before I give up this type of tileset ):
As for the searching features, since Object properties are stored as plaintext within map files, would grepping the files without loading them as Maps/Tilesets be an option? That’s what I basically do now, outside of Tiled. The regex is different depending on the file type, but the regex could be decided based on extension (I think ignoring files with unfamiliar extensions would be fair for this), and I don’t think it’s important to distinguish between filesets and maps when doing property searches (and tilesets won’t match object regex anyway).
While typing this up, I remembered another QoL thing I’ve run into, though this one’s probably more of a me problem:
In Photoshop, I can quickly show/hide several layers by clicking on one visibility icon and dragging to others, and it’ll set their visibility to be the same:

I often try to do this in Tiled out of habit, but it drags the layer in the layer stack instead. It would be nice if Tiled had this same feature, or at least didn’t drag the layer if I click+drag on the eye or lock icons rather than the rest of the layer.