What a fall from grace this card had.
Gothetelle was originally one of the most hyped cards in the format when EP came out, with fairly good reason, as it mimicked the most powerful effect of The Truth (that is, locking out dragons from taking a prize), while having more streamlined evolution lines and better overall consistency. Unlike Vileplume, Gothetelle's ability only worked in the active spot, reminiscent of Spiritomb or an early Vileplume. The Trainer Lock was also one way, not affecting the player using Gothetelle, which allowed Gothetelle to play trainers with relative impunity. Gothetelle's attack was weak, and relied on a lot of energy, but it did have the magic 130 HP, preventing a KO. I've heard from some Gothetelle players that if the lock was broken at any time, it was much harder to recover due to the fact that so many resources were burned in establishing the lock in the first place. However, with only Magnezone being able to score a KO, and with Magnezone having no real consistent way to Lost Burn, it was a bad matchup, but not catastrophic.
Then NV happened.
Magnezone gained Eelektrik, making Lost Burn infinitely more viable. ZPST had the option of Rocky Helmet, making smart early plays easier to break the lock. Kingdra Prime, although not from NV, became a popular partner with Tyram some time before, giving it an answer to Gothetelle. Mew could OHKO Gothetelle. The release of Kyurem made Solosis's 30 HP really bad, and put too many damage counters on the field at once. Half the EX pokemon in ND could easily OHKO Gothetelle, and all of them were pretty splashable into meta decks or made new meta decks altogether. On top of this, Tyram, one of the two decks that Goth was originally supposed to counter, fell in popularity. ZPST could easily splash Mewtwo EX or run Zekrom EX, both making Gothetelle an easy matchup. Raikou EX next set would make Gothetelle unplayable, with Reuniclus falling to one hit from Voltage Arrow.
Now Gothetelle did have some good combos, Reuniclus namely, and Reuniclus opened the door to the dragons and Max Potion, and it could combo with Gardevior and Electrode Prime, providing better offense and not even bothering with the damage lock, which ultimately might be the better and only play given the ease of OHKOing Gothetelle lately. Trainer Lock could still be annoying so this deck idea might have some purpose, who knows? However, many would argue that Mewtwo EX is the far superior partner to Gardevior, and while I think that the lack of the lock will make Gardevior vulnerable to pretty much anything, the community has spoken. Gothetelle, which was one of the greatest hard counters to ZPST and originally one of the best decks in the format, has now been regulated to the display binder while Reuniclus moved to bigger and better things with Vileplume, however, Reuniclus's days might be numbered as certain key EX pokemon come out, but we'll see.
Rating: 5/10