Thanks, I read through all of that.
I noticed a couple of things though. For one, Pelipper and Torterra were mentioned (Pelipper being touted quite strongly as a great defog user) and they are both in NU now. The rest of the Pokemon mentioned - Vibrava, Wartortle, Avalugg, Armaldo, etc - were all mentioned in a negative light. Vibrava being useless, Wartortle being "borderline useful" and the rest being very susceptible to SR as well as the Pokemon that can lay them.
Also, Pokemon like Articuno, Rotom-F, etc would of course be much too strong for the PU game if SR was removed, but then those Pokemon would be suspect and probably delegated to NU themselves if SR was banned.
I see the argument that SR allows for an "intelligent" gameplay, but when your choices to counter SR are FORCED to take much more damage than most premier spinners/defoggers in their respective tiers; arguably the best examples of one trick ponies (useless outside of that); and only even considered because they can do that, I think it speaks volumes. Remember, good rapid spinners go in higher tiers just for being good counters to SR, hence why PU has so little.
The Pokemon in PU are literally the worst Pokemon in the game and their positions may indeed be specifically, or mostly, because they get completely destroyed by SR (like Articuno), but what that also points towards is that SR might just be too strong for the tier itself. There are not many Pokemon that resist SR in PU compared to other tiers, most that do are NFE of Pokemon in higher tiers. Really, it does say a lot.
Personally, I would say that using SR in the lowest tier is arguably the least intelligent use of SR in Smogon competitive because of those reasons mentioned above. Many Pokemon are low in usage because of that weakness, those who aren't weak to it are low because they're just flat-out bad Pokemon, and there are such limited options to actually prevent or remove them. Plus, why use spikes or toxic spikes when SR is bound to take 12.5-25% health of probably over half of the regularly used list of Pokemon in PU upon switching? A lot of talk was about SR preventing switch and momentum move spam, but it's obviously not the only damaging entry hazard, and I think spikes are fundamentally fine. Really SR just seems infinitely worse because so many Pokemon are actually in PU because SR makes them horribly bad.
What is also interesting (and sorry if I'm wrong here) is that everyone in those posts you linked seemed willing to try it, yet the discussion ended on that page. Furthermore, it was specifically about SR and only SR. What about my other option of limiting the total amount of hazards set? No need for a fancy formula, but just say that a team can only place one at a time? I know it's not 'hard' to counter the stacking of multiple at all, but if I'm honest it's just my want to play some niche, crappy Pokemon in a tier without an abundance of, or reliance on, entry hazards.
Lastly, I don't think a specific "type" of Pokemon is going to overtake the PU meta if something dramatic like this does happen. Maybe some Flying type Pokemon would be used, but Normal? Remember this tier has 0 fully evolved Fighting types and 1 fully evolved Dark type. If a Normal type Pokemon like Raticate got used more, that'd be a lot more fun than having SR in every single game, and it'd be more interesting too. Plus, we all know that Raticate or any other Normal type that got used a lot would have its counters.
P.S. Normally when a(n intentionally) competitive game has one thing that dictates the metagame for every single player in every single tier of that game, that thing gets revised. SR is probably the single move that dictates every single meta (in turn making spin, defog, taunt etc very important). This meta is dictated the worst by it.
P.P.S. What are the biggest threats to watch out for in a metagame without Stealth Rock? And how can you be sure that removing Stealth Rock wouldn't also push those Pokemon up to BL4 or NU?