To be clear, I was questioning whether or not specific decks might be able to get by with another Pokemon EX. I am not trying to imply that Mewtwo EX is bad. It may be the single most powerful Pokemon this format, and of course it might truly be required to win at a major event. I don't believe this is set in stone yet, and thus it is well worth questioning and testing. If you have indeed been doing this, I apologize if I seem dismissive: I am not trying to be. If you stated that earlier or in another place, I am sorry I missed it: please link me, since my own ability to test has been so severely compromised as of late that I freely (but sadly) confess I am running on Theorymon. X_X
From experience I do question the "necessity" of having the supposed "must have" card. I already laid out why:
1) Japan=/=Rest of the world - it's a good indicator, but sometimes things work differently
2) Hyped cards have fallen short before
3) Only one person can win a tournament, only a handful make top cut: if you're not convinced your going to be one of those players anyway, I'd focus on learning how to play without Mewtwo EX: it will improve your skill more in the long run and save you money.
4) I keep pointing out that while in the immediate short run prices are likely to spike, I don't claim to know Nintendo: sometimes an important card for the metagame is practically spammed, sometimes it never gets re-released no matter how much we ask for it.
Please take all of those into account. I don't know any of your personally. If I was talking to someone I knew who for some reason was on the fence, and I knew this person was a prime candidate for making it to Worlds... yes I'd tell them to buy it now if they could afford it, and if they couldn't I'd tell them to find a way to afford it.
I was questioning whether or not a player might legitimately be at least able to consider using a different Pokemon EX in specific decks. Decks where Mewtwo EX isn't giving as good a return as it could. With a source of Psychic Type Energy and some form of acceleration to get it onto Mewtwo EX it can hit for 120 better than Reshiram or Zekrom (plain versions). Of course, most decks aren't going to do that: even if the deck is running Rainbow Energy and/or Prism Energy, that's a trick your reserve for KOs that you simply have to make.
X-Ball is the attack most people are focusing on, and that's 20 points of damage per Energy on both Active Pokemon. So assuming you can change out your Active Pokemon, Mewtwo EX can be a surprise drop from your hand, have a Double Colorless Energy slapped on it (or if in the appropriate deck, other forms of Energy acceleration) and hit hard.
Mewtwo EX should be a problem for plain Zekrom: assuming both have Eviolite, Mewtwo EX hits a Zekrom that just used Bolt Strike (in a hurry, forgive me if I am remembering the wrong name) for 100 points of damage (assuming minimum Energy attachments for both), which after losing 20 points of damage to Eviolite but factoring in the 20 points Zekrom did to itself, is still 100 points of damage.. That Zekrom player can now unload a Bolt Strike into Mewtwo EX for (after Eviolite on both of them) 100 points of damage to Mewtwo EX and another 20 to itself.
Unless the Mewtwo EX has additional support (like retreating to get bounced by Seeker or a Max Potion followed by more Energy acceleration), it can hit Zekrom one more time, then gets taken down itself. Reshiram fairs even better: since it discards two Energy a Mewtwo EX with minimal investment (re: two Energy) only does 60 points of damage, or 40 points if Reshiram has Eviolite, because there is only a total of three Energy between them. Again assuming Mewtwo EX is coming up after Reshiram has unloaded on something else, Mewtwo EX will have to invest more Energy or Reshiram gets at least one shot at Mewtwo EX, probably two and maybe even three!
Yes, Mewtwo EX isn't reliant upon support for these direct match-ups, but at the same time one can't ignore this is how those two Basic Pokemon are most likely to be encountered, in decks that fully support them. I don't expect some of the most popular recent decks to poof away overnight.
This brings me to my main point: while I don't consider Reshiram EX or Zekrom EX to be anywhere near Mewtwo EX's league, that's because they are very dependent upon their decks for support. Can't just toss them into anything with Double Colorless Energy or non-matching Energy Type acceleration, ya know? In a tournament setting, where either is backed by the appropriate deck, skilled players should at least be able to approach trading Mewtwo EX for Prizes with them. Mewtwo EX comes up and eats something (that hopefully already earned a Prize, given past experiences with those decks), and either Reshiram EX or Zekrom EX can leave Mewtwo EX reeling.
Reshiram EX or Zekrom EX are probably going to take a big hit back, but again, they aren't a super splashable utility attacker, but a big [DEL]ugly[/DEL] pretty beatstick. Likely Mewtwo EX and whatever it faces will have Eviolite, so that means Mewtwo EX is getting slammed for 130 points of damage that first hit. With minimal Energy requirements for X-Ball, it hits Reshiram EX for (6 x 20 -20) 100 points of damage, so even if Reshiram EX hit itself for (50-2) 30 points of damage, it isn't gone yet and can finish off Mewtwo EX. Zekrom EX fairs better since it discards two of its own Energy, hitting Mewtwo EX just as hard but in the same circumstances only taking 60 points of damage.
Am I going with circumstances favorable to those two Pokemon EX over Mewtwo EX? Yes, but its favorable because they are being put into decks that favor them, not splashed about into anything. If Mewtwo EX is run alongside Energy acceleration it will probably triumph over those two... but bear in mind the cost. A 180 HP Pokemon with an Eviolite means that between Mewtwo EX and the Defending Pokemon, X-Ball requires 10 Energy! Even against something with four Energy, that's six total Energy Mewtwo EX has to supply.
Can that be done? Certainly! The cost is Mewtwo EX becoming self-defeating in purpose: a large part of its power comes from it hitting so hard for so little Energy.
tl;dr: Mewtwo EX is really good, but it isn't healing the sick and raising the dead like some people seem to expect of it. It is a very expensive card right now and if you're the type who regularly attends Worlds or at least wins major semi-local events like States, even if you don't have a lot of disposable income it is a good buy. I do believe other alternatives exist, especially for specific decks; Mewtwo EX's strength is in its flexibility, its utility, but in a specialist deck you regularly won't need those things.
Plus any deck that can effectively (re: bust it out fully powered in one turn) run and power up Rayquaza & Deoxys LEGEND should. Best case scenario you get a lot of wins when suddenly you take your last three Prizes in one shot. Worst case scenario you at least get to enjoy the occasional three-for-two deal where you OHKO one Mewtwo EX.
