Jolteon

Despite its amazing Speed and ability to somewhat threaten rain teams, Jolteon holds no niche in the metagame. It's very weak, unable to significantly damage metagame staples like Tyranitar, Ferrothorn, Latios, Hippowdon, Celebi, Jirachi, Gastrodon, Reuniclus, and Excadrill. This weakness also makes it easy to block its Volt Switch with a Ground-type, even if running Hidden Power Ice. It also has no notable defensive utility outside of an immunity to Electric, making it very difficult to switch into battle. It's also outclassed by other Electric-types, mainly Thundurus-T due to it also having Volt Absorb and bringing a Ground immunity, much more power, better coverage, and more set versatility between its Substitute wallbreaker and Agility sets. Rotom-W also outclasses Jolteon due to its much better defensive profile letting it check and pivot around common threats, like Alakazam, Keldeo, Gliscor, Excadrill, and Heatran, as well as being able to burn its checks with Will-O-Wisp. Jolteon is also outpaced and revenge killed by common Choice Scarf users like Keldeo, Garchomp, and Latios, making its Speed less of an advantage.