@frog Reaver - I'd say that tracking information like this will tell you rather a lot about that specific group. Tracking across various campaigns will tell you even more about that specific group. See, to me, I don't care about any else's group. I've seen far too many "Oh this is broken" or "5e is D&D on easy mode" type arguments to think that what happens at someone else's table even remotely resembles what happens at mine.
Theorycrafting assumes too much. Sure, it's a great start to give you a direction for what you need to look at, but, by and large, I find theorycrafting very pointless. It simply will not predict what happens.
But, I totally agree that a single encounter or even a single day will tell you anything useful. I did say that you should track about 20 rounds of combat. More if you like. I find 20 to be decent enough that it shows general trends. But, absolutely it's only showing general trends for that specific group.
But, trends for a specific group is far, far more useful to that group than theorycrafting which tries to make general statements based on nothing more than hypotheticals. I mean, heck, you talk about 300 foot darkvision being an issue.
Why? IME, it's almost impossible for encounters at that range. There's never sight lines out that far, for one. For another, I almost never see any combat starting at that kind of range unless maybe the PC's were deliberately hunting something. I can't imagine that actually having any impact at my table. It just wouldn't. But, OTOH, at other tables, maybe it would.
Again, that's why I'm such a big proponent of empirical evidence over theory.