I feel that I need to do a little clarification, because I feel that we are talking about vastly different things due to our different usage of the word broken. For me, broken is not the same as overpowered. Overpowered means that a card or strategy is so strong that it cannot be countered, or if it can, is so difficult to do that most of the time is not worth the effort. Broken is when a card 'cracks' the overall state of the game, by making things too fast, too slow, too volatile, too strategy-less etc. to the point where it makes the game itself less stable. I class DCE as a broken card because it one of the causes for the pacing of the game not allowing anything that requires time to function (except Primal Groudon, but only because of Omega Barrier), however, DCE is not an overpowered card due to its many many counters and drawbacks in Aegislash EX, Enhanced Hammers, Xerosic, Giratina-EX (if it ever takes off) etc. Due to how it speeds up pacing, it breaks the game by disallowing a mechanic that has been at the core of the game for quite some time, evolution, from functioning as it should, making it so that stage 2s (when played as stage 2s) aren't viable. Laser, Muscle Band and Strong Energy does the same, allowing us to output lots of damage too early into the game, but they have their counters so they too aren't overpowered.
Besides Stage 2s, we have seen a sharp decline in set up attacks being used. There's M Mane, M Sceptile, Virizion EX, and we
may see Volcarona AOR seeing play as well, but besides there we just don't have much that works. We are at the point where set up attacks are simply pushed out (note how those that work also have the ability to set up for 2HKOs) due to how important every attack you make is with the pacing of the game in its current state.
There aren't any overpowered cards in this format. Not M Rayquaza, not Toad, not Night March, not Primal Groudon, not anything a lot of people would like to suggest. There are really strong strategies, but none of those warrant banning or early rotations or anything along those lines because really, there isn't anything dominating the metagame (this even happens to be one of those years where a rogue came up top). It's a really fun format, one of the better ones I've seen so far. As for Shiftry... I guess you can say I have something to say about it, but is not limited to just Shiftry but rather every donk strategy from the past to the formats to come. I'd like for the No Pokemon in Play win condition to be applied at the end of a player's turn rather than immediately like how the Deck Out win condition only applies at the start of your turn. Would give some hope to Unlimited. That's a different story, though.
There are however a number of broken cards in this format. They aren't too many that they 'shatter' the game (see Base Set era and the end of the DP era) and I'd like to keep it that way. It is however approaching that, which is my primary concern.
After playing this for more than a decade, I'm quite familiar with the routine of analyzing strategies and figuring out how to counter them. It's my favorite part of the game.
That and building decks that can, for lack of a better term, surprise people. Love combos too, just so long as they aren't too easy to pull off (half the fun of a combo is in the challenge, no?) and depending on how difficult it is to get the combo going, combos deserve to be strong. Otherwise, no one would play them.
I have a feeling I'm mistaken about the meaning of the words I just used (language barriers
). If I'm wrong, correct me, but doesn't "putting aside your feelings" means doing whatever you must to succeed?
Edit:
Also to those saying that DCE was here since forever, I was sort of curious about it, so a couple of days ago I went ahead and looked up the actual DCE reprints in Japan since Base Set 2 was English only.
1st DCE print: October 20 1996
2nd DCE print: October 9 2009
That's 13 whole years. The game hasn't even been around for 20.