I've been experimenting a good deal with a modification of
Denis' team in UU.
First of all, it does requires skill, good prediction and strategic thought to pull off versus good structured teams. Counting your screens right and getting your taunt at the precise moment could mean the game.
Secondly, it is not true that it is easier to pull in UU than in OU. Denis himself said the biggest counter to it's team is Amoonguss. While it is very viable in OU, it's a pokemon sitting two tiers below the relavant tier! Many of the additional counters to the stratagey sit right here in our own UU and they are very viable without specifically aiming to deal with this.
The Team I ended up with is -
Before going over the counters and threat list, I would like to voice my opinion that if anything about this ( or in fact about any of the new drops, like others already said in this thread ) should be suspected/tested/banned imo is probably just the move Geomancy.
Counters :
Toxic Umbreon - Even if Espeon is behind a sub, when Umbreon uses Toxic, it triggers Magic Bounce and bounces back into Umbreon. As Umbreon gets poisoned, it triggers it's synchronise and badly poisons Espeon as well. Meaning the Espeon user should not even bother subbing as it just lowers it's diminishing health. This puts a timer on Espeon and once it dies, Espeon's team probably doesn't have another chance at winning. Furthermore, Espeon needs 168 SpA Ev's to ensure +2 Dazzling Gleam will 2hko. Otherwise, Umbreon can stall more poison turns with WishTect or even win 1vs1 with Heal Bell+Moonlight. The only chance of survival is to try to Geomancy twice.
Dragon Tail users - Unlike Roar, Magic Bounce and Taunt don't block it. To
be failproof, I need to Encore with Whimsicott, which is immune to it due to fairy typing. Then I just have enough turns to Memento, bring Smeargle in, Geomancy and immideatly Baton Pass into Togekiss. Giving the boosts to Togekiss instead of Espeon is already subpar but not passing to it any Cotton Guard boosts is a really weak and frail situation to be in. Furthermore, while this strategy can deal with Miltoic and Goodra, both Aggron and Rhyperior tend to carry Dragon Tail just as much as they tend to carry Roar so it's really a 50/50 if I should Taunt/Baton Pass to Espeon or Baton Pass to Togekiss. If I lose my guess, I lose my game. In fact, (M)Aggron is such a pain as Heavy Slam nails Togekiss so if it carries both moves, this team loses.
Spdef Jirachi - " If Jirachi is using a SpD set it will be able to pp stall my 200BP Stored Power + Dazzling Gleam from Espeon. For that reason I will need to use the move Geomancy twice, then Espeon will have power enough to 2HKO it. "
Prankster Taunt - Shuts down the whole team and each needs to be carefully played around. Sableye is outsped by Whimsicott and 2hkod by 0Spa Togekiss. Tornadus is 1hkod by Aero and outsped by Whimsicott(beware of STAB). Lastly, Espeon can come in and out to bounce Taunts and other shannenigans back but fears Knock Off from Sableye and any strong hitting move from Tornadus, however it deals best with Whimsicott. All in all, an untimely Taunt can mean the game and most of the time, the best case scenario will be passing just Geomancy to Espeon, which isn't enough to break Blissey.
Lead Galvantula - Sticky Web will erase all of Geomancy's speed boosts as it will affect Smeargle once and then the baton passed Espeon twice. Since it critical to Taunt Galvantula, it can just Thunder Aero and Bug Buzz Azelf and limit them to either no Stealth Rocks and one screen or no screens at all. In fact, after Aero dies it's better to just bring Whimsicott and risk not having screens.