Justice and Rule
Legend
What I gathered from previous discussions on the topic is the possible encounter band is simply wound way too tight in PF2. Instead of level +4, folks would like more in the range of level +6-8 which aligns with older RPG systems. Seems PWL variant can help achieve this.
PWL probably does given how the math works in that, but having an 8-level range along with the "Weak" and "Elite" tags (Wounded dragons, elite mercenaries, etc) should work to give things variety. The bigger thing I think is that what are your expectations of going into an encounter? Does every encounter have to have a reasonable chance of win/loss?
This isn't to say that it's perfect for it, but rather I want to get at what people look at in a sandbox. For me, the players should be able to go out and find things, research things back home, have encounters won't be able to win and will either have to avoid or retreat from them. I think PF2 does that fairly well, and allows a GM to know going in how difficult an encounter is going to be before the players get there. Now for some that might be not what they want in a sandbox, that no one should quite know what is going to happen when going into an encounter. I respect that and understand it, though it's not for me nowadays.