First off, Pieces, thank you for an articulate and reasonable post.
Most of this thread, sans derails, has been arguing over whether a metagame with Keldeo is healthier than a metagame without Keldeo. On the last page jpw234 made some good points on how limiting Keldeo is to team-building: In order to create a viable non-HO OU team, you need to have at least one of 7 counters or a few of several more situational checks, each of which creates further restraints on teambuilding. He says, and I agree, that banning Keldeo would help free this up and create more scope for creativity.
The problem is, this is also true for something like a third of OU. You need to have a Terrakion check. You need to have a Cloyster counter. You need to have an answer to chlorophyll Venusaur. Breloom, Kyu-B, and select others collectively eliminate entire styles of play, let alone force teams to carry a check or two. This is definitely 'unhealthy' for the metagame, if you define health as freedom and versatility of play. Yet, while all of these pokemon may be 'unhealthy', none of them are broken.
You make it sound as though everybody has just conceded that Keldeo is no different than the rest of these pokemon. The issue is that Keldeo is (unlike the rest of these pokemon) able to 2HKO every check but Amoonguss based on its set and with minimal Pursuit support can get past its three biggest counters, Celebi/Latias/Jellicent. This is not true for Terrakion, Cloyster or Venusaur. It also lacks important weaknesses that these other pokemon have - Terrakion is weak to the two most common priority moves, Cloyster's Ice type gives it a terrible SR and Fighting/Rock/Steel weaknesses, Venusaur is heavily reliant on weather and still hard walled by pink blobs/Latias/Heatran, Breloom is slow and one-dimensional with pretty much non-existent bulk (I'm not addressing Kyu-B because I think it's broken as well). Keldeo on the other hand has:
- STABs that complement each other well
- No weakness to priority moves or susceptibility to entry hazards
- Is not reliant on weather to perform well (although is better in rain)
- The ability to hit on the opposite side of the spectrum than its premier attack stat with STAB in Secret Sword (this is its biggest differentiation from Terrakion - you can't just use a "special wall", it must be a fairly bulky mixed wall that is resistant/immune to fighting AND water)
- Versatility between a multitude of sets that play entirely differently
- Synergizes well with a variety of playstyles to pressure or take down its counters
To say that "there are other pokemon which do these things" is to ignore the many unique advantages that Keldeo brings to the table.
If we were really committed to creating the freest OU possible, we'd have to keep banning until we had something that looked more like UU than the current OU. That's not why suspect testing exists, though.
That's a misrepresentation of the position. Nobody's clamoring to ban Donphan or Espeon, or even top-tier threats like Scizor or Tyranitar.
There's a quote from Aldaron in the OP that I feel a lot of people are ignoring. It says we shouldn't be testing based on which meta we like better. The point of suspect testing isn't about creating the freest, funnest, or even best metagame possible. It's about banning the broken mons and leaving us a playable game. It's possible for one pokemon to overcentralize the meta around itself to the point of being broken, but OU is so constrained that you're almost always going to be running Celebi, Jellicent, Latias, or a few lesser checks such as Tentacruel/Rotom-W/etc. anyways, and even if Keldeo happens to be the pokemon placing the most limits on teambuilding at the moment, the second most restraining 'mon is not far behind.
If Aldaron actually meant what I bolded there, than he's wrong. But I suspect you misrepresented what he meant. Crimping diversity or the entertainment value of the metagame are characteristics we should and do look to when determining brokenness. Outside of this, I and others have provided many reasons why Keldeo is actually broken under your definition.
If we look at all the previous banned suspects, there was a solid argument that they were broken in and of themselves. Tornadus-T was unkillable and kept momentum all game, Landorus could outright beat all its counters with some luck, Deoxys-D was a guaranteed two layers every game, and so on and so forth. There is no such argument for Keldeo, making the best and only argument for banning it that it overcentralizes the metagame around itself, but that's a flimsy one when it has as many checks as it does. If requiring one or two checks from over ten was enough to make a pokemon broken, we'd be saying goodbye to almost every offensive threat in OU.
I made it, and overcentralization is still a very strong argument in and of itself.
