I don't post lists because I know there are plenty of people coming to this thread and skipping through the real discussion just looking for lists. I'm not a fan of giving away things I've actually committed time to. However, I'll gladly talk about my list.
I'm just going to say that those people gain nothing by taking your list and
not reading discussion (unless the deck is as autopilot as I honestly believe it is.) I have never understood this mentality. It's one thing to try to hide your entire strategy (I don't want to share the deck I am thinking I will play for Cities, that's for sure...) but another to hide your decklist of an established archetype, unless you're doing something REALLY bizarre with it, which it doesn't sound like you are. If you're going to help people by contributing, why hold back the most helpful information?
I'll try to approach the rest of your thoughts with a relatively open mind but your somewhat aggressive language is certainly very off-putting.
2 Mewtwo is a great fit for this deck. Why? Well, #1 he's got one of the best attacks in the game. #2 Eviolited Shaymin is a major problem for this deck and darkrai-hydregion is most likely running it. If you take 2 prizes, you risk an Eviolited Shaymin absolutely wrecking through your field. It's going to one shot your keldeo and if you can't return KO it, it's going to KO a blastoise or another keldeo the following turn. Look what 2 Mewtwo builds of Darkrai-Hydregion did, they dominated battle roads. Lastly, if you can't counter a big Mewtwo, you lose. Having Mewtwo in this deck prevents your opponent from running wild on you for big damage. Kyurem NVI is clunky and committing 3 energy to it in hopes that you can get off 2 glaciates is too risky and in my testing it just came off as more wishful thinking rather than a legitimate strategy.
Keldeo's attack is also one of the best. Just saying that Mewtwo is "one of the best attackers" isn't enough to me. As an attacker, it's redundant and takes up space in a deck that is greedy for every spot it can get.
Eviolited Shaymin is a problem for many decks. The thing is, Keldeo can drop 4 energy on another Keldeo to OHKO Shaymin (through Eviolite). Mewtwo would need a fifth energy to do the same thing. Mewtwo does not actually help you answer Shaymin.
Comparing Darkrai/Hydreigon with Mewtwo to Keldeo/Blastoise with Mewtwo ignores some very important differences between the decks. Hydreigon/Darkrai can minimalize investment in a Mewtwo by removing energy from it once a KO is completed. It can reasonably use Psydrive to make a return KO marginally harder. Mewtwo is a "big attacker" that doesn't discard - something the deck badly needs in some metagames. Keldeo/Blastoise, however, already has an insane attacker (Keldeo). Mewtwo doesn't add anything the deck doesn't already have except some additional type coverage.
The only valid reason, to me, to run Mewtwo is to counter other Mewtwos. I can only say I don't think that's a good idea in theory. I can't tell you anything about my testing experience there.
12-13 energy is enough for this deck, including at least 2 DCE. DCE allows you to attack for 70 on T2 with Keldeo with or without Blastoise. This is enough to KO a tynamo, sableye, deino or hit an EX. Assuming you can get your Blastoise online by T3, you should be able to follow up the 70 with a 110 ko the next turn on any non-eviolited EX. Even if you aren't able to get the 110 T3, 70 T2 will put early pressure on your opponent and force them to rethink their next two turns to avoid falling behind.
Think about this deck with 11 water energy. Assuming you only put two Water on your first Keldeo, your next two Keldeo have 9 energy to work with. This might sound like a lot, granting you 4-5 energy per your other Keldeos, but this is assuming that you draw your ENTIRE DECK and none of your energy are prized or wasted on things like retreating a Keldeo for Mewtwo (which isn't a problem when you don't run Mewtwo), or powering up a Mewtwo for that matter. If you only draw 75-80% of your deck, discounting how many of those cards will be Trainers, Supporters, and Pokemon rather than Energy, you're only going to hit 75-80% of your energy at best (less than that most of the time), meaning you get on average about 7, maybe 8 Water energy in a game. This is to say nothing of the timing of those energy, which could be all at once, or could be one per 6-7 cards of your deck you draw or search. You aren't giving yourself enough energy to draw into it reliably, and are requiring yourself to draw into things like Energy Retrieval and Cilan to keep yourself going.
10 draw supporters, 2 Skyla, 1 Cilan. This is your supporter line. Should be plenty to keep you going. Your deck is fast, it's not meant to play a long drawn out game, therefore as long as you play conservatively and don't Juniper away too many Skyla/Cheren/Bianca you shouldn't draw dead.
I'd really like to liken this deck to an Eels build. Eels requires a couple of Stage 1 evolutions and a bunch of discarded energy - Keldeo requires a stage 2, and a bunch of energy in hand. Eels has the benefit of being able to discard energy as it goes, thus thinning its deck and utilizing draw cards like Bianca or Juniper more effectively. Keldeo has to make sure it gets Blastoise into play before being able to attach its energy, but after doing so it too could theoretically abuse Bianca and Juniper.
Other than the clunkiness of requiring energy in-hand (which is a very serious difference mind you) and the much more daunting task of setting up a stage 2 over a stage 1 (though granted Squirtle is ridiculously good as an evolving Basic), these two decks ought to be pretty similar in terms of consistency and speed. So what's the point I'm trying to make?
Last format at least (and, I'm seeing it continued in this format), Eels was one of the slowest, clunkiest decks there were. You didn't run Eels for early game power, and you still don't today. You run Darkrai or Tornadus if you want a fast early game. You run Eels because you want powerful attacking options lategame.
Keldeo acts in much the same way in terms of setup and card requirements, and you're trying to play it as a Darkrai-speed deck. You aren't going to get it there. A deck with early pressure is going to maul Keldeo [I actually have been building a Virizion prototype that really impressed me].
4 Scoop ups, 3 energy retrievals. 4 scoop ups @ 50% each means you're likely to hit 2 a game on average, usually wiping 2 of your opponents attacks off the board.
I'm going to stop you here and remind you that those SSUs are not simply guaranteed. You draw 75-80% of your deck most games (perhaps down to 90??) so you're actually going to average less than 4 SSU per game, not including prizes, and you're going to therefore hit less than 2 SSU flips per game. I have been in a bit of a hissy fit over SSU recently so I acknowledge that I might not be giving the card enough credit in general, but I think your logic here is a tad flawed, and I'm just highlighting why I say so.
3 energy retrievals work well to ensure you never have trouble grabbing energy either from your deck or discard in the middle and end of games.
4 ultra, 2 level is the play. 1 super rod. No scrappers.
I don't mind the idea of swapping one of my Super Rods for a Retrieval. That is a change I would probably like once I made it.
If I were to try to construct your list in my mind, I'm seeing 3 Keldeo 2 Mewtwo 3-1-3 Blastoise which gives a total of 12 Pokemon; 10 draw supporters with 2 Skyla and 1 Cilan for 13 supporters (25 so far); 4 SSU, 3 Retrivals, 4 Ultra 2 Level, 1 Super Rod is 14 more cards (39 now), and 13 energy (so 52). That's 8 spaces for what I'm sure must be 3 Rare Candy, 1 Computer Search, and 4 Catcher. So in essence your list is mine with an extra attacker over a Squirtle, two less draw supporters, and SSU and Cilan in place of Energy.
My list only really sets up 60% of the time. I am willing to acknowledge that a high energy count is part of what makes my list inconsistent, but a -2 in energy without
adding any additional consistency cards in its place doesn't seem like it would make a great deal of difference. So I'm sorry, but I have a hard time believing on the face of it that your list is more consistent than mine.
I will try some of the architectual changes I'm seeing here though, I can definitely see that taking out some energy and adding another Retrieval would change the dynamic of the deck quite a bit.
