I really don't think Revenankh is very broken at all, I actually think he fits very nicely into the metagame. He certainly is very good, but I don't think he is very much better than much of the top 10 most used. Pokemon like Skarmory and Gyarados really do manage to stop him cold. My one major complaint about him would probably be Shedskin, because I do think it makes maybe a little unfairly difficult to deal with considering he practically has a status immunity, but otherwise I think he actually fits nicely into the metagame. He reminds me alot of a physical version of Suicune - if you are unprepared for him (namely if you lack a phazer) you'll have major problems with it, but if you are prepared, he isn't too large of a threat.
Pyroak I also don't have a problem with, I don't think he is really even all that good - not that he needs to be improved or anything, just that I don't think he is even close to broken. Having a Stealth Rock weakness automatically makes a pokemon much easier to deal with. He is very effective when supported by a full stall team, but outside of stall, I haven't found him very useful, mostly because his typing doesn't really lend itself to countering too many specific threats, and often his slot would better be taken up by something like Gliscor or Vaporeon, but overall I think Pyroak was pretty successfull.
Syclant is the only one I really take issue with. For some reason, nobody really seems to be exploiting him, in the same it seems that people weren't really exploiting wobbuffet when he was legal, but I think Syclant is extremely broken. This is mostly because of movepool, I think. In every other CAP we have been very careful about giving pokemon moves that might overpower them, or that might not fit flavorwise, however, Syclant has absolutely none of that same restrain.
We argued for the longest time about whether Revenankh should get Thunder Punch, and whether Pyroak should get Earthquake, and in the end we decided that they would make the pokemon too hard to counter. Well, if that was the standard we were going to take with the other CAPs, then we should go back and evaluate Syclant with this same frame of mind. I mean really, why does Syclant have Earth Power and Superpower. We wouldn't dream of giving these moves to Pyroak because we thought that would Heatran unviable as a counter, but we didn't have a problem giving them to Syclant. I personally think Syclant should have a complete reassessment, both movepool and stats, to determine if he is maybe a little too much. The main moves I think should be rethought are Earth Power, Superpower, Focus Blast, and Tail Glow. These moves make it so that even pokemon like Heatran and Tentacruel, who should be hard counters, can be taken down easily, leaving the only iffy counters at Bronzong and Jirachi, and even then only barely.
Basically, they way I see it, Pyroak is like a Swampert/Celebi/Zapdos type pokemon - very good, but not even remotely close to broken, just very solid, useful pokemon. Revenankh is like a Gengar or Lucario (not in playstyle, just in metagame impact), in that he is very good, definitely one of the best, but within reason. I think Syclant is essentially like Garchomp, or maybe even like the Latis or Darkrai or one of those other debatables - he is just a little too good. The difference though is that we have the power to tweak Syclant, and hopefully make him more fitted to OU.
Of course thats just my opinion on it, and I'm sure many people might disagree. I just don't think Syclant is really being abused like he could, and in this case I think theorymon is a pretty useful tool. In my opinion, arguements like "I've never really had a problem with it" just further illustrate that people aren't using him well, because to me, just looking at Syclant, he looks like easily a Garchomp class pokemon.