The claim that the current DMG acts as a reference and that the main problem is the layout just doesn’t make sense to me.
By way of example, the DMG only has 4 pages on traps and only includes 9 sample traps. Some reference! And traps are something that you find in most playstyles.
I no longer have my 4e DMG, but as I recall, it had quite a few hazards. By way of comparison, Level Up has 40 pages of hazards. PF2 includes traps in the Core Rulebook and still manages to devote 9 pages to them and include 20 examples.
As I mentioned earlier, the environmental hazards section in the DMG is also quite poor, with extreme cold and extreme heat barely impacting characters, and the hazards described mostly unable to work as standalone hazards.