Whizbang Dustyboots
Gnometown Hero
No one needs to use the WotC stat blocks as-is. Even WotC has changed their stat blocks mid-edition, because no stat block expression is perfect.What I'm wondering is where things like stat blocks are in this spectrum. They collect rules terms, but in a rather specific manner. And being able to print NPC and monster stats exactly like people expect them is a huge benefit.
Look at the stat blocks on the upcoming Monster Overhaul. That's not the layout for any existing rule set, but any OSR DM could use it instantly and I'd say that most WotC-era DMs who were inclined to could use it without much effort as well. (Hit points look like the only major issue for WotC-era versions of D&D.)
If you want to make a 5E-compatible stat block, it doesn't have to look anything like WotC's expression of it. I daresay you could probably come up with a better one than they use. (They all have too few passive abilities pre-figured for my tastes, and I'd like to see monsters' initiative scores pre-filled as well.)