Raikou can tank hits from tornadus-t unlike jolteon so outspeeding it doesn't really matter. If ferrothorn lacks power whip it loses to raikou. We're talking about volt absorb raikou meaning using Twave on it is a no no. Raikou's bulk is worth it in the end it can take a powerful priority moves from dragonite and breloom and isn't 2HKO'd by thunderus-t's hp ice. Now that all of that is covered, Jolteon's only niche is outspeeding +1 gyarados or dragonite, which really isn't that big of a deal to warrant its stay in ou. Ditto can actually take advantage of those boosts.