I'm not entirely sure why some anti-ban sentiment seems to hinge on the idea that the meta will somehow swing back towards bulkier teams in the future even with Miraidon around, or that people just haven't experimented with options enough. With Ubers this gen having the power level that it does, there really is only so many options you can exhaust without resulting in teambuilding issues vs other major threats. And for Miraidon specifically, with its massive versatility and instant power you can only prep for it so much.
Back in Gen8, even with CalyS as threatening and centralizing as it was forcing teams to run Yveltal, they weren't seriously impeded from a teambuilding standpoint. Most every team had a Caly answer built into them which also functioned as an incredible glue for teams, and Caly really had to work to get into that game winning state. It could rarely threaten to insta blow up teams, especially since it wasn't that uncommon to see teams have a back up check (Ho-oh is the main one coming to mind). This on top of the fact that it was the only pokemon sporting such an absurd speed stat, meant that you didn't regularly have to fear speed ties or making frustrating 50/50 plays or awkward lines of play. Why am I mentioning this?
During my laddering there was a frustrating amount of times where Mira/Korai (or two Miraidons) would end up facing off, and this led to an annoying amount of 50/50 calls on whether to tera and try to snipe the opposing dragon or to try and switch into an immunity to one stab hoping to make the right call and absorb the hit, or to sack a weakened pokemon hoping to reposition. This was more prominent than I care for (oh and the speed ties and 50/50s were made worse when Draco Meteor misses if staying in and winning that dice roll). Now I ran a HO team during laddering, I tried originally going with a bulkier team with not great results. Too many of Miraidon's checks on these teams are abused by the presence of other dangerous, difficult to handle threats.
My point is this: Even if SS CalyS is arguably a more centralizing pokemon than Miraidon, you had to really work to get a CalyS into position to win back in gen8 and thus feeling more skill rewarding, while current gen9 games feels far more volatile and swingy based on things that aren't as much in player control (the aforementioned speed ties, 50/50 plays as a result of Miraidon and Koraidon's power, etc.), it feels comparatively less rewarding and much more frustrating, and Miraidon is a major contributor to this factor. And Koraidon is guilty of this too, and if necessary (probably) it's always possible to look at it in the future post Miraidon.
I don't agree with the way you state this like it's an objective fact. Plenty of people enjoy the tier the way it is now, I'm sorry if you don't enjoy it but there's plenty of people who disagree with you.
It's completely fair if you enjoy the tier, But there's an undeniable feeling that there's been a dwindling enjoyment factor for more players. It's not really a good sign when enjoyment on the latest survey went
down instead of up despite the ban of Last Respects, and stability has remained around the same (and generally not too high). As for your list of defensive checks, I'd like to go over that briefly.
Clodsire: Miraidon and Kyogre check. This is fair, except it runs into the major problem of its immense passivity which makes it very easy to exploit by offensive teams which either turn it into set up fodder with certain sets, or simply overwhelm it. It also tends to invite dangerous pokemon that Miraidon tends to be paired with (also momentum drain).
Ting-Lu: This has fallen way off because it's terribly easy to punish and exploit. It frankly checks just about nothing outside Miraidon well, and without the reliable recovery that Clod at least has, isn't harm to overwhelm. It's also a giant momentum drain and frankly, it just sucks if I'm being blunt.
Iron Treads: I'd argue this mon, while good in a Miraidon meta, is only good in a Miraidon meta. It's role compression is born entirely of the presence of electric terrain, and without that it's a passive weak mon that checks nothing else realistically (I certainly can't think of any). Not to mention that its claim of spin is increasingly difficult to work with when Webs HO can just spinblock through Ghostceus or other Tera Ghost mons.
Blissey: Super passive and generally not great outside stall. Also lumping in protect here but, outside Treads what mon is even fitting Protect right now? I can't think of any off the top of my head.
I'd love to touch on LO Miraidon because that's what I used during my run and it put in significant work every single game. Against opposing offense it slices right through steels who try to absorb Draco (ZacianC, NDM), while it still places huge burden on balance that isn't running Ting-Lu because CM+LO Draco drops almost anything from full. And there's Agility sets which as was pointed out earlier, kind of makes most of your offensive counterplay section moot. BTW calling Webs teams and Agility sets gimmicky is pretty bizarre when they've been prominent for a while now (Agility sets taking a lot of attention and rightly so).
Anyways I feel like I got a bit off track from my original thoughts, but I'm voting
ban on Miraidon. It may not solve every issue the tier has, but it's a good step in the right direction and I really feel its removal will also ease the burden on building which will help make checking Koraidon and ZacianC easier (and Kyogre if we're bringing up huge threats).
checking caly 
in g8.
btw
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