My thoughts on the two ladders now that I have reqs:
The main team I use is a Rain team with Scarf Keldeo on it, so that's what I used on Current. On Suspect, I used essentially the same team, but with Scarf Analytic Starmie (with Surf, Ice Beam, Thunder and Hydro Pump) instead. Gotta say, it functioned almost exactly the same. I had to get a little more damage on the opposing team before I went for the Surf cleanup, but it was basically just as good of a revenge killer, actually gave alternate cleanup win conditions with its coverage moves, and hit really hard thanks to Analytic. Yes, my team became a little weaker to Ferrothorn and Kyurem-B, but it also now had an easier time with Jellicent. There were also the advantages of surprise value (Scarf Starmie is really rare), outspeeding Scarf Latios and not having to speed tie against Scarf Terrakion, and just the presence of Starmie on my team discouraging the opponent to lay hazards to an extent (they don't know I don't have Rapid Spin).
All of that said, Keldeo was better for the team, obviously (otherwise I'd be using Starmie on the regular team). The extra power, and resistances to Stealth Rock, U-Turn and Pursuit (as opposed to weakness to the latter two) were the main reasons for that (as well as Secret Sword to an extent, but that was basically a coverage trade-off). But the point is that it was replaceable, and that its replacement, though not quite as effective, was in the same league as far as revenge killing and lategame cleaning was concerned.
I don't have experience using the Specs or Expert Belt sets, so I won't theorymon about them. I'll talk about what I do know, which is fighting against them, as well as against the Scarf set:
The main team I use only has Toxicroak for a Keldeo counter, and it performs just fine. Because I use a variation of Swords Dance Toxicroak, it's true that it is 2HKOed by Specs HP Ghost (or Ice or Electric) after Stealth Rock (Bulk Up sets aren't, by the way), but that's a lot easier to do on paper than in practice. For one thing, they have to predict the switch (not all that hard, admittedly), and for another, I'll just switch out to Ferrothorn or Jirachi. Toxicroak is still alive, which discourages Hydro Pump or Surf spam, and it's a lot riskier for the opponent to use Hidden Power next time, since I now know the set, and might not switch. Also, because of Dry Skin and Drain Punch, and beating common Keldeo partners (Tentacruel, most Politoed, most Tyranitar), Toxicroak has a good chance of coming in later and gaining back the health it lost anyway.
And as far as Scarf, E-Belt and Calm Mind sets are concerned, Toxicroak counters them fully, which means that as long as I play intelligently with Toxicroak, I never have much trouble with Keldeo unless the opponent legitimately outplays me. And I use a balance team, so I disagree with people who say that Keldeo is awful for balance to fight.
I know that these are very specific examples of using/replacing/dealing with Keldeo, and obviously don't apply to everyone. I'm not advising everyone to replace Keldeo with Starmie on the Suspect ladder, or to use Toxicroak as their Keldeo counter, I'm just giving my experiences about it. Other people have given their experiences about how they use Jellicent or Latias to beat it, and collectively, these experiences give much better insight about using/dealing with Keldeo than a bunch of theorymoning does.
But yeah, I'm very much convinced that Keldeo is not broken. It has hard counters that are both common and have access to recovery, and though many are Pursuit-weak, most have a way around it, and even for ones that don't, it's not like Keldeo has U-Turn, so risk and skill are needed to trap and beat them. And the stuff about Keldeo beating its own counters is bullshit, because even though it can 2hko a lot of them with the correct item and Hidden Power, they won't stay in to take the second hit, and can come back and recover later, as well as discourage water spam simply by still being alive. A Keldeo-less metagame (a real one, not the Suspect Test one, since most people would have used existing Keldeo-less teams or found a replacement like I did) wouldn't look that different to the metagame with Keldeo. Most of its counters would still be used to counter rain. One of the only significant changes would be a probable rise in Ferrothorn usage, since it would become a much better rain counter. I think a lot of the people who believe that Keldeo is broken are still thinking of Keldeo in the context of the LandKeldTar metagame, where there was a much better case for its brokenness, with it and Landorus overloading their shared counters, and Landorus U-Turning into Tyranitar to trap and kill them.
Also, just a nitpick: E-Belt Icy Wind + HP Bug even with Stealth Rock and Sandstorm can't 2hko Latias. Some residual damage is needed on top of that. Not a big deal, but I think that needed clarifying. And things like Latias to an E-Belt set and Jellicent to a Specs set can serve as checks even when they're weakened to the point that they can't counter, and then Recover so they can counter again next time. And since Keldeo's counters are much easier to bring in than Keldeo is (obviously, since they're defensive and it's offensive), getting them in and getting health back isn't too difficult a task.
PS. I feel like with the 2-1 ratio requirement gone, it's way too easy for people to get reqs, since the ladder is ridiculously inflated. It would be difficult not to be at 2000±60 after playing enough games.